diff --git a/cv3/program.c b/cv3/program.c
index 44580b1..1bce719 100644
--- a/cv3/program.c
+++ b/cv3/program.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <assert.h>
+#include <ctype.h>
 
 #define STACK_SIZE 10
 
@@ -43,6 +43,12 @@ int is_operator(char* input) {
             strcmp(input, "*") == 0 || strcmp(input, "/") == 0);
 }
 
+int is_valid_float(char* input) {
+    char* endptr;
+    strtod(input, &endptr);
+    return *endptr == '\0';
+}
+
 void perform_operation(struct stack* s, char* operator) {
     if (s->size < 2) {
         printf("Chyba: nedostatok operandov\n");
@@ -81,8 +87,8 @@ int main() {
     while (fgets(input, sizeof(input), stdin) != NULL) {
         input[strlen(input) - 1] = '\0';
 
-        float value;
-        if (sscanf(input, "%f", &value) == 1) {
+        if (is_valid_float(input)) {
+            float value = atof(input);
             push_stack(&mystack, value);
         } else if (is_operator(input)) {
             perform_operation(&mystack, input);