I have check test case all pass but when going submit then showing test case error(Formatted Numbers)

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1

#include<stdio.h>

int main(){
long long int n;
scanf(“%lld”,&n);
int reverse = 0;
int counter = 0;
int last_digit;

while(n!=0){
   last_digit = n%10;
   reverse = reverse * 10 + last_digit;
   n/=10;
   counter++;
}

while(reverse!=0){
    last_digit = reverse%10;
    printf("%d",last_digit);
    reverse/=10;
    counter--;
    if(counter > 0 && counter%3 == 0){
        printf(",");
    }
   
}

return 0;

}