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












































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































/**************************************************************
	Problem: 1300
	User: zhangyilei
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/