diff --git a/du4/program.c b/du4/program.c
index 8477261..6a5bbd5 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -1,91 +1,87 @@
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include <stdlib.h>
 #include <math.h>
 
 int main() {
-    int ch = getchar();
-    char priklad[300];
+    char line[300];
     int count = 0;
+    while (fgets(line, sizeof(line), stdin)) {
+        count++;
+        char *start = line, *end = NULL;
+        int has_operator = 0;
+        float num1 = 0, num2 = 0, expected_result = 0;
+        char op, *next;
 
-    for (int idx = 0; 1; idx++) {
-        priklad[idx] = ch;
-        if (ch == '\n') {
-            count++;
-        }
-        ch = getchar();
-        if ((priklad[idx] == '\n' && ch == '\n') || ch == EOF) {
-            break;
-        }
-    }
-
-    char *start = priklad, *end = NULL;
-
-    for (int c = 0; c < count; c++) {
-        int skip = 0, z = 0;
-
-        for (int idx = 0; start[idx] != '\n'; idx++) {
-            if (start[idx] == '+' || start[idx] == '-' || start[idx] == '*' || start[idx] == '/') {
-                z = 1;
-            }
-            if ((start[idx] < '0' || start[idx] > '9') && start[idx] != ' ' && start[idx] != '=' && start[idx] != '+' && start[idx] != '-' && start[idx] != '*' && start[idx] != '/' && start[idx] != '.') {
-                skip = 1;
-                printf("CHYBA\n");
-                while ((*start) != '\n') {
-                    start++;
+        while (*start != '\n') {
+            if (*start == '+' || *start == '-' || *start == '*' || *start == '/') {
+                if (has_operator) {
+                    printf("CHYBA\n");
+                    goto next_line;
                 }
-                start++;
-                break;
-            }
-        }
-
-        if (skip == 1) {
-            continue;
-        }
-        if (z == 0) {
-            while ((*start) != '\n') {
-                start++;
+                has_operator = 1;
+                op = *start;
+            } else if ((*start < '0' || *start > '9') && *start != ' ' && *start != '=' && *start != '.') {
+                printf("CHYBA\n");
+                goto next_line;
             }
             start++;
+        }
+
+        if (!has_operator) {
             printf("CHYBA\n");
-            continue;
-        }
-        float num1 = strtof(start, &end);
-        if (end == start) {
-            printf("KONIEC\n");
-        }
-        while ((*start) != '+' && (*start) != '-' && (*start) != '/' && (*start) != '*') {
-            start++;
-        }
-        char znak = (*start);
-        start++;
-
-        float num2 = strtof(start, &end);
-        start = end;
-        while (((*start) < '0' || (*start) > '9') && (*start) != '-') {
-            start++;
+            goto next_line;
         }
 
-        float vysledok2 = strtof(start, &end);
-        start = end;
-        start++;
-        float vysledok = 0;
-
-        if (znak == '-') {
-            vysledok = num1 - num2;
-        } else if (znak == '+') {
-            vysledok = num1 + num2;
-        } else if (znak == '*') {
-            vysledok = num1 * num2;
-        } else if (znak == '/') {
-            vysledok = num1 / num2;
+        num1 = strtof(line, &next);
+        while (*next == ' ') next++;
+        if (*next != op) {
+            printf("CHYBA\n");
+            goto next_line;
         }
-        vysledok = (round(vysledok * 100)) / 100;
-        if (vysledok2 - vysledok < 0.001 && vysledok2 - vysledok > -0.001) {
+        next++;
+        num2 = strtof(next, &next);
+        while (*next == ' ') next++;
+        if (*next == '=') {
+            next++;
+            expected_result = strtof(next, &next);
+            while (*next == ' ') next++;
+        } else {
+            printf("CHYBA\n");
+            goto next_line;
+        }
+        if (*next != '\n') {
+            printf("CHYBA\n");
+            goto next_line;
+        }
+
+        float result;
+        switch (op) {
+            case '+':
+                result = num1 + num2;
+                break;
+            case '-':
+                result = num1 - num2;
+                break;
+            case '*':
+                result = num1 * num2;
+                break;
+            case '/':
+                if (num2 == 0) {
+                    printf("CHYBA\n");
+                    goto next_line;
+                }
+                result = num1 / num2;
+                break;
+        }
+        result = roundf(result * 100) / 100;
+        if (fabs(result - expected_result) < 0.001) {
             printf("OK\n");
         } else {
             printf("ZLE\n");
         }
+        next_line:
+        continue;
     }
     return EXIT_SUCCESS;
 }