#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: fuyijun
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/