diff --git a/a1/program.c b/a1/program.c
new file mode 100644
index 0000000..cf55ba9
--- /dev/null
+++ b/a1/program.c
@@ -0,0 +1,148 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define SIZE 1000
+
+typedef struct{
+    char* p_na_line;
+    struct link* p_na_next_struct;
+}link;
+
+int main()
+{
+    link* pointer_to_start_of_chain = malloc(sizeof(link));
+    memset(pointer_to_start_of_chain,0,sizeof(link));
+    reading_strings_and_storing_them_in_memory(pointer_to_start_of_chain);
+    int result=0;
+    link* next_link = pointer_to_start_of_chain;
+    while(next_link != NULL){
+        result=analizing_string(next_link->p_na_line);
+        if(result==0){
+            printf("ZLE\n");
+        }else if(result==1){
+            printf("OK\n");
+        }else{
+            printf("CHYBA\n");
+        }
+        next_link=next_link->p_na_next_struct;
+    }
+    return 0;
+}
+
+int reading_strings_and_storing_them_in_memory(link* pointer_to_start_of_chain){
+    link* next_link = pointer_to_start_of_chain;
+    char buffer[SIZE];
+    link* ancestor=NULL;
+    while(1){
+        if(fgets(buffer, SIZE, stdin)==NULL){
+            if(ancestor!=NULL){
+                free(ancestor->p_na_next_struct);
+                ancestor->p_na_next_struct=NULL;
+            }
+            break;
+        }
+
+        int size=strlen(buffer)+1;
+
+        next_link->p_na_line=malloc(size);
+        next_link->p_na_next_struct=malloc(sizeof(link));
+
+        memcpy(next_link->p_na_line, buffer,size);
+        ancestor=next_link;
+        next_link=next_link->p_na_next_struct;
+    }
+}
+int analizing_string(char* pointer){
+    float number1, number2, result3;
+
+
+    int counter=0;
+    char operant;
+    int i=0;
+
+    while(pointer[i]!='\0'){
+        if(pointer[i]=='+'||pointer[i]=='/'||pointer[i]=='*'||pointer[i]=='-'){
+            operant=pointer[i];
+            counter++;
+            if(counter>1){
+                return -1;
+            }
+        }
+        i++;
+    }
+
+    char delim[] =" +=-*/\n";
+
+    char *first_number_cucumber=strtok(pointer, delim);
+
+    if(first_number_cucumber==NULL||is_number_question_mark(first_number_cucumber)==0){
+
+        return -1;
+    }
+
+    char *second_number=strtok(NULL, delim);
+
+    if(second_number==NULL||is_number_question_mark(second_number)==0){
+        return -1;
+    }
+
+
+    char *result=strtok(NULL, delim);
+    if(result==NULL||is_number_question_mark(result)==0){
+        return -1;
+    }
+
+    char *token = strtok(NULL, delim);
+    if(token!=NULL){
+        return -1;
+    }
+
+
+    number1=atof(first_number_cucumber);
+    number2=atof(second_number);
+    result3=atof(result);
+
+    if(operant=='+' &&result3==number1+number2){
+        return 1;
+    }
+    if(operant=='-'&&(result3==number1-number2)){
+        return 1;
+    }
+    if(operant=='*'&&(result3==number1*number2)){
+        return 1;
+    }
+    if(operant=='/'&&(result3==number1/number2)){
+        return 1;
+    }
+    return 0;
+}
+
+
+int is_number_question_mark(char *pointer){
+    for(int i=0; pointer[i]!='\0'; i++){
+       if (!isdigit(pointer[i])&&pointer[i]!='.'&&pointer[i]!=',') {
+            return 0;
+        }
+    }
+    return 1;
+}
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