#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,s;
    cin>>n>>s;
    if(n>=90){
    	s=n*3;
    }
    else if(n>=80&&n<90){
    	s=n*2;
    }
    else if(n>=70&&n<80){
    	s=n;
    }
    else{
    	n=50;
    }
    cout<<s;
return 0;
}

/**************************************************************
	Problem: 1300
	User: chenzelin
	Language: C++
	Result: Wrong Answer
****************************************************************/