Fast power writing

#include<bits/stdc++.h>
using namespace std;
#define  IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
typedef long long ll;
const int N=1e5+10;

ll qmi(ll a,ll b, ll c)
{
	int res=1;
	while(b)
	{
		if(b&1) res=(ll)res*a % c;
		b>>=1;
		a=a*a%c; 
	}
	return res;
}

int main()
{
	IOS 
	ll a,b,c;
	cin>>a>>b>>c;
	cout<<qmi(a,b,c);
	return 0;
}

Application of fast power