#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,m;
	float q;
	cin>>n>>m;
	if (m==1){
		q=n+m*0.0325*n;
	}
	else if (m==2){
		q=n+m*0.0375*n;
	}
	else if (3<=m && m<=4){
		q=n+m*0.0425*n;
	}
	else {
		q=n+m*0.0475*n;
	}
	printf("%.1f",q);
	return 0;
}
/**************************************************************
	Problem: 1341
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:23 ms
	Memory:2072 kb
****************************************************************/