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

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