#include<bits/stdc++.h>
using namespace std;
int a;
int main(){
	cin>>a;
	switch (a/10) {
		case 9: case 10:
			cout<<a*3;
			break;
		case 8:
			cout<<a*2;
			break;
		case 7:
			cout<<a;
			break;
		default:
			cout<<50;
			break;
	}
	return 0;
}

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