#include <bits/stdc++.h>
using namespace std;
int main(){
    int a,n;
    float m;
    cin>>a>>n;
    if(n==1){
        m=a+(a*0.0325)*n;
    }if(n==2){
        m=a+(a*0.0375)*n;
    }if(n==3||n==4){
        m=a+(a*0.0425)*n;
    }if(n>=5){
        m=a+(a*0.0475)*n;
	}printf("%.1f",m);
}
/**************************************************************
	Problem: 1341
	User: sucongyi
	Language: C++
	Result: Accepted
	Time:28 ms
	Memory:2072 kb
****************************************************************/