题解.或许是

#include<cstdio>
using ll = long long;
ll a,b,p;
ll qpow(ll a,ll b,ll p){
    ll ans=1;
    while(b){
        if(b&1)ans=ans*a%p;
        a=a*a%p;
        b>>=1;
    }
    return ans;
}
int main(){
    scanf("%lld%lld%lld",&a,&b,&p);
    printf("%lld^%lld mod %lld=%lld",a,b,p,qpow(a,b,p));
    return 0;
}