Why is it not passing all test cases

#1

#include <bits/stdc++.h>
using namespace std;
long long int expo(int a,int b){
int ans=1;
while(b>0){
if(b&1){
ans=ans*a;

}
a=a*a;
b=b>>1;

}
return ans;
}
int main(){
int a,b,c;cin>>a>>b>>c;
long long int f=expo(a,b);
//cout<<f & c<<endl;
cout<<(expo(a,b))%c;
}

#2

Refer to Modular Exponentiation | Last testcase did not pass

#3

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