#include <iostream>
using namespace std;
 
int main() {
    int n;
    cin >> n;
 
    int pocketMoney;
    if (n >= 90) {
        pocketMoney = n * 3;
    } else if (n >= 80) {
        pocketMoney = n * 2;
    } else if (n >= 70) {
        pocketMoney = n;
    } else {
        pocketMoney = 50;
    }
 
    cout << pocketMoney << endl;
 
    return 0;
}    
/**************************************************************
	Problem: 1300
	User: baizhoudeyueguang
	Language: C++
	Result: Accepted
	Time:18 ms
	Memory:2072 kb
****************************************************************/