#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	if(n>=90){
		n*=3;
		cout<<n;
	}
	if(n>=80&&<90){
		n*=2;
		cout<<n;
	}
	if(n>=70&&<80){
		cout<<n;
	}
	if(n<70) {
		cout<<"50";
	}
	return 0;
} 
/**************************************************************
	Problem: 1300
	User: houlingqi2
	Language: C++
	Result: Compile Error
****************************************************************/