diff --git a/a1/program.c b/a1/program.c
index 28d47d3..0323371 100644
--- a/a1/program.c
+++ b/a1/program.c
@@ -2,49 +2,33 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdbool.h>
+#include <ctype.h>
 #include <math.h>
 
 bool check_spaces(const char* str) {
     int len = strlen(str);
-    bool is_operator = false; 
-    bool is_operand = false;  
 
-    for (int i = 0; i < len; ++i) {
-        char current_char = str[i];
-        
-        
-        if (current_char == ' ') {
-            if (!is_operator && !is_operand) {
+    for (int i = 0; i < len - 1; ++i) {
+        if (str[i] == '+' || str[i] == '-' || str[i] == '*' || str[i] == '/') {
+            
+            if (i == 0 || str[i - 1] != ' ')
+                return false;
+            
+            if (str[i + 1] != ' ')
                 return false;
-            }
-        }
-        
-        else if (current_char >= '0' && current_char <= '9') {
-            is_operand = true;
-            is_operator = false;
-        }
-        
-        else if (current_char == '+' || current_char == '-' || current_char == '*' || current_char == '/') {
-            is_operator = true;
-            is_operand = false;
-        }
-        
-        else {
-            return false;
         }
     }
 
     
-    if (!is_operand) {
+    if (str[len - 2] == '+' || str[len - 2] == '-' || str[len - 2] == '*' || str[len - 2] == '/')
         return false;
-    }
 
     return true;
 }
 
 char* check_math_problem(const char* problem) {
     if (!check_spaces(problem)) {
-        return "ZLE";
+        return "CHYBA";
     }
 
     if (strlen(problem) == 0) {
@@ -75,7 +59,7 @@ char* check_math_problem(const char* problem) {
             break;
         case '/':
             if (fabs(n2) < 1e-9) { 
-                return "ZLE";
+                return "CHYBA";
             }
             result = n1 / n2;
             break;
@@ -104,7 +88,3 @@ int main() {
     return 0;
 }
 
-
-
-
-