#include<bits/stdc++.h>
using namespace std;
int main(){
	double a,b;
	cin>>a>>b;
	double n=1;
	double sum=0;
	for(int i=1;i<=b;i++){
		for(int j=1;j<=i;j++){
			n*=a;
		} 
		sum+=n;
		n=1;
	}
	cout<<fixed<<setprecision(2)<<sum+1<<endl;
	return 0;
}