diff --git a/du4/program.c b/du4/program.c
index 6fe39c4..497a439 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -29,6 +29,11 @@ int main() {
 	break;
 	}
 	for (int i = 0; i < strlen(znaky); i++) {  
+	if(znaky[i] == ','){
+	if(check != 1)
+	printf("CHYBA\n");
+	check = 1;
+	}
 	if (znaky[i] == '*' || znaky[i] == '/' || znaky[i] == '+' || znaky[i] == '=') {
                 symbol[sym] = znaky[i];
                 znaky[i] = ' ';
@@ -47,8 +52,10 @@ int main() {
         while (*zaciatok_cisla != '\0') {
     	cislo = strtof(zaciatok_cisla, &koniec_cisla);
     		if (zaciatok_cisla == koniec_cisla) {
-        		printf("CHYBA\n");
-        		check = 1;
+        		if(check != 1){
+			printf("CHYBA\n");
+			}
+			check = 1;
         		break;
     		} 
     		else {