#include <bits/stdc++.h>
using namespace std;
int main(){
	int a,s;
	cin>>a;
	if(a>=90){
		s=a*3;
		cout<<s;
	}
	if(a<90&&a>=80){
		s=a*2;
		cout<<s;
	}
	if(a<80&&a>=70){
		s=a*1;
		cout<<s;
	}
	if(a<70){
		s=50;
		cout<<s;
	}	
}
/**************************************************************
	Problem: 1300
	User: tonghuawei
	Language: C++
	Result: Accepted
	Time:17 ms
	Memory:2072 kb
****************************************************************/