#include<bits/stdc++.h>
using namespace std;
int main()
{
	long long n;
	cin>>n;
	if(n>=90) n=n*3;
	else if(n>=80) n=n*2;
	 	 else if(n>=70) n=n;
	   		  else if(n<70) n=50;
	cout<<n;
	return 0;
}

/**************************************************************
	Problem: 1300
	User: ccf
	Language: C++
	Result: Accepted
	Time:13 ms
	Memory:2072 kb
****************************************************************/