Why this code is not working?

[pratham.sharma6113 (Pratham Sharma)]

#include
#include<math.h>
using namespace std;
int main() {
long long int a,b,c;
cin>>a>>b>>c;
long long int ans=1;
for (int i = 1; i < b; i++)
{
ans=((a%c)*(a%c))%c;
}
cout<<ans;
}