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

	return 0;
}

/**************************************************************
	Problem: 1300
	User: lvrenxiang
	Language: C++
	Result: Accepted
	Time:16 ms
	Memory:2072 kb
****************************************************************/