Help me in solving LJAJAG27 problem

My issue

my code is correct but still its not working and showing failed test cases and after i click on debug my code it shows wait for 9 seconds then at around 5-6 seconds the website just gets blanked and dont show anything and when i refresh the page the code is gone

My code

#include <stdio.h>

int main() {
	// your code goes here
    int a,b;
    char operator;
    scanf("%c",&operator);
    scanf("%d %d",&a,&b);
    switch(operator) {
        case '+':
        printf("%d\n",a+b);
        break;
        case '-':
        printf("%d\n",a-b);
        break;
        case '*':
        printf("%d\n",a*b);
        break;
        case '/':
        if(b != 0){
            printf("%d\n",a/b);
            
        }
        else {
            printf("Error: Division by zero is not allowed.\n");
        }
        break;
        case '%':
        if(b != 0){
            printf("%d\n",a%b);
        }
        else {
            printf("Error: division by zero is not allowed.\n");
        }
        break;
        default:
        printf("Invalid operator! Please use one of the following: +,-,*,/,%\n");
    }
    return 0;
}


Learning course: Learn C Programming
Problem Link: https://www.codechef.com/learn/course/rcpit-programming-c/RCPITLPC37/problems/LJAJAG27