diff --git a/du4/program.c b/du4/program.c
index 8df203f..d8c943e 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -1,144 +1,171 @@
-/*
-gcc -Werror -std=c11  -Wall  in-out.c   -lm   -o in-out -lm && ./in-out
-*/
-#include <stdio.h>
-#include <stdarg.h>
-#include <stdlib.h>
-#include <ctype.h>
-#include <math.h>
+#include <stdio.h> 
 
-struct res{
-    double na,nb,result;
-    char sign;
-}list [10];
+#include<string.h> 
 
-int fill(double*,double*,char *,double *);
-double count(const double*,const double *,char);
-int aget(double *);
-int sget(char *);
-int efinde(void);
-char checkend(void);
+#include<math.h> 
 
-int main(){
-    int cond;
-    char fcond=1;
-    int i;
-    for(i=0;fcond!=EOF;i++){
-        fcond=checkend();
-        if(fcond==EOF)
-           break;
-        
-        cond=aget(&list[i].na);
-        if(cond<0){
-            printf("CHYBA\n");
-            return 0;}
-        cond=sget(&list[i].sign);
-        if(cond<0){
-            printf("CHYBA\n");
-            return 0;}
-        cond=aget(&list[i].nb);
-        if(cond<0){
-            printf("CHYBA\n");
-            return 0;}
-        cond=efinde();
-        if(cond<0){
-            printf("CHYBA\n");
-            return 0;}
-        cond=aget(&list[i].result);
-        if(cond<0){
-            printf("CHYBA\n");
-            return 0;}
-        if((fcond=checkend())!='\n' && fcond>0){
-            printf("CHYBA\n");
-            return 0;}
-        if(fcond==-1)
-            break;
-        //printf("%lf %c %lf = %lf\n",list[i].na,list[i].sign,list[i].nb,list[i].result);
-    }
-    for(int x=0;x<i;x++){
-        double fin=count(&list[x].na,&list[x].nb,list[x].sign);
-        //printf("%lf %lf\n",fin,list[x].result);
-        if((long)(fin*1000000)!=(long)(list[x].result)*1000000){
-            printf("ZLE\n");
-            return 0;
-        }
-    }
-    printf("OK\n");
-    
-}
-char checkend(void){
-    char c;
-    int count=1;
-    c=getchar();
-    while((c=getchar())){
-        ++count;
-        if(c==EOF || c=='\n'){
-            int a=c;
-            if((c=getchar())==EOF){
-                int b=c;
-                    if((c=getchar())==EOF){
-                        ++count;
-                        fseek(stdin,-count,SEEK_CUR);  
-                        return c;
-                    }  
-                ++count;
-                fseek(stdin,-count,SEEK_CUR);  
-                return b;
-            }
-            ++count;
-            fseek(stdin,-count,SEEK_CUR);
-            return a;
-        }
-        else if(!isspace(c)){
-            fseek(stdin,-count,SEEK_CUR);
-            return c;
-        }
-    }
-    return -2;
-}
-double count(const double*na,const double *nb,char sign){
-    
-    if(sign=='+')
-        return *na+*nb+0.00000000001;
-    else if(sign=='-')
-        return *na-*nb;
-    else if(sign=='*')
-        return *na*(*nb);
-    else if(sign=='/')
-        return *na/(*nb);
-    
-    return -1;
-}
+#include<stdlib.h> 
+
+char* compactString(char *src,int leng) { 
+
+char *new_str = (char*)calloc(leng+1,sizeof(char)); 
+
+int k=0; 
+
+for(int i=0;i<leng;i++){ 
+
+if(src[i]!=' '){ 
+
+new_str[k] = src[i]; 
+
+k++; 
+
+} 
+
+} 
+
+return new_str; 
+
+} 
+
+double operation(double first,double second,char c){ 
+
+double x =0; 
+
+if(c=='*'){ 
+
+x=first*second; 
+
+return x; 
+
+} 
+
+else if(c =='-'){ 
+
+x=first-second; 
+
+return x; 
+
+} 
+
+else if(c=='/'){ 
+
+x=first/second; 
+
+return x; 
+
+} 
+
+x= first+second; 
+
+return x; 
+
+} 
+
+double round_to(double value, double eps) 
+
+{ 
+
+return floor(value/eps + 0.5) * eps; 
+
+} 
+
+double compare_percent(double a, double b, double eps) 
+
+{ 
+
+double diff = round_to( (a - b) * 2 / (a + b), eps); 
+
+return diff < 0 ? -1 : diff > 0 ? +1 : 0; 
+
+} 
+
+int check(char *str){ 
+
+int flag=0; 
+
+char symb[5]="*-+/="; 
+
+for(int i =0;i<strlen(str);i++){ 
+
+for(int k =0;k<5;k++){ 
+
+for(int j =0;j<5;j++){ 
+
+if(str[i]==symb[j]&&str[i+1]==symb[k]){ 
+
+return 0; 
+
+} 
+
+} 
+
+} 
+
+if(str[i]=='='){ 
+
+flag=1; 
+
+} 
+
+if((str[i]>='a'&&str[i]<='z')||(str[i]>='A'&&str[i]<='Z')||str[i]==','){ 
+
+return 0; 
+
+} 
+
+} 
+
+return flag==1?1:0; 
+
+} 
+
+int main() 
+
+{ 
+
+char str[100][100]; 
+
+ for(int i =0;fgets(str[i],100,stdin);i++){ 
+
+  if(str[i][0]=='\n'){ 
+
+  break; 
+
+  } 
+
+ char *new_str = compactString(str[i],strlen(str[i])); 
+
+ double first =-5,second =-5,res=-5; 
+
+ char c='E'; 
+
+ sscanf(new_str,"%lf%c%lf%*[=]%lf",&first,&c,&second,&res); 
+
+ if(c!=43&&c!=42&&c!=45&&c!=47||check(new_str)==0){ 
+
+  printf("CHYBA\n"); 
+
+ continue; 
+
+ } 
+
+ double my_res = operation(first,second,c); 
+
+ if(compare_percent(res,my_res,0.01)==0){ 
+
+  printf("OK\n"); 
+
+ } 
+
+ else{ 
+
+  printf("ZLE\n"); 
+
+  } 
+
+} 
+
+return 0; 
 
-int aget(double *na){
-    char a[30];
-    char c;
-    char *p;
-    p=a;
-    while(isspace(c=getchar()));
-    if(isdigit(c)){
-        *(p++)=c;
-        while(isdigit(c=getchar())|| c=='.') *(p++)=c;
-        *p='\0';
-        *na=atof(a);
-    }else
-        return -1;
-    fseek(stdin,-1,SEEK_CUR);
-    return 1;
-}
-int sget(char *sign){
-    char c;
-    while(isspace(c=getchar()));
-    if(c=='+' || c=='-' || c=='/' || c=='*')
-       *sign=c;
-    else
-        return -1;
-    return 1;
-}
-int efinde(void){
-    char c;
-    while(isspace(c=getchar()));
-    if(c!='=')
-        return -1;
-    return 1;
 }
\ No newline at end of file