diff --git a/cv3/program.c b/cv3/program.c
index 6d023d1..78c21ea 100644
--- a/cv3/program.c
+++ b/cv3/program.c
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
+#include <ctype.h>
 
 #define STACK_SIZE 10
 
@@ -18,7 +19,7 @@ void init_stack(struct stack* s) {
 
 
 void push_stack(struct stack* s, float value) {
-    assert(s->size < STACK_SIZE); 
+    assert(s->size < STACK_SIZE); /
     s->values[s->size] = value;
     s->size += 1;
 }
@@ -33,41 +34,27 @@ float pop_stack(struct stack* s) {
 
 void print_stack(struct stack* s) {
     for (int i = 0; i < s->size; i++) {
-        printf("%.2f ", s->values[i]); 
+        printf("%.2f ", s->values[i]);
     }
-    printf("\n"); 
+    printf("\n");
 }
 
 
-void process_operation(struct stack* s, const char* operation) {
-    float b = pop_stack(s);
-    float a = pop_stack(s);
-    if (strcmp(operation, "+") == 0) {
-        push_stack(s, a + b);
-    } else if (strcmp(operation, "-") == 0) {
-        push_stack(s, a - b);
-    } else if (strcmp(operation, "*") == 0) {
-        push_stack(s, a * b);
-    } else if (strcmp(operation, "/") == 0) {
-        if (b == 0) {
-            printf("Chyba: Delenie nulou.\n");
-            exit(1); 
-        }
-        push_stack(s, a / b);
-    }
+int is_number(const char* str) {
+    char* endptr;
+    strtof(str, &endptr);
+    return endptr != str && *endptr == '\0'; 
 }
 
+
 int main() {
     struct stack mystack;
-    init_stack(&mystack); 
+    init_stack(&mystack);
 
-    char input[256];
-    int has_input = 0; 
+    char input[20]; 
 
-    printf("Poľská kalkulačka\n");
     while (1) {
-        
-        printf("Zadajte číslo alebo operáciu (+, -, *, /): ");
+        printf("Enter a number or an operation (+, -, *, /): ");
         if (!fgets(input, sizeof(input), stdin)) {
             break; 
         }
@@ -75,36 +62,50 @@ int main() {
         
         input[strcspn(input, "\n")] = 0;
 
-        
-        char* endptr;
-        float value = strtof(input, &endptr);
-        if (endptr != input) { 
+        if (is_number(input)) {
+            
+            float value = strtof(input, NULL);
             push_stack(&mystack, value);
-            has_input = 1; 
-            print_stack(&mystack);
-            continue; 
-        }
-
-        
-        if (strcmp(input, "+") == 0 || strcmp(input, "-") == 0 || 
-            strcmp(input, "*") == 0 || strcmp(input, "/") == 0) {
-            if (mystack.size < 2) {
-                printf("Chyba: Nedostatok hodnôt v zásobníku.\n");
-                break; 
-            }
-            process_operation(&mystack, input);
             print_stack(&mystack);
         } else {
-            printf("Chyba: Neplatný vstup.\n");
-            break; 
-        }
-    }
+            
+            if (mystack.size < 2) {
+                printf("Error: Not enough values on the stack to perform operation.\n");
+                break; 
+            }
+            float b = pop_stack(&mystack);
+            float a = pop_stack(&mystack);
+            float result;
 
-   
-    if (has_input) {
-        printf("no input\n");
-    } else {
-        printf("no input\n");
+            switch (input[0]) {
+                case '+':
+                    result = a + b;
+                    break;
+                case '-':
+                    result = a - b;
+                    break;
+                case '*':
+                    result = a * b;
+                    break;
+                case '/':
+                    if (b == 0) {
+                        printf("Error: Division by zero.\n");
+                        break;
+                    }
+                    result = a / b;
+                    break;
+                default:
+                    printf("Error: Unknown operation '%s'.\n", input);
+                    push_stack(&mystack, a); 
+                    push_stack(&mystack, b);
+                    break;
+            }
+
+            if (result) {
+                push_stack(&mystack, result);
+                print_stack(&mystack);
+            }
+        }
     }
 
     return 0;