P1226 wa一个点求助！！！

#include <iostream>
using namespace std;
long long a,b,p;

long long ksm(long long m){
    long long t;
    
    if(m==1 || m==0) return a%p;

    t =ksm(m/2) % p;

    if(m%2==1) return (t*t*a) % p ;
    else return (t*t) % p;
}

int main(){
    cin>>a>>b>>p;
    cout<<a<<'^'<<b<<" mod "<<p<<'=';
    cout<< ksm(b) <<endl;
    
    return 0;
}