#include <iostream>

int main() {
    int x, y;
    std::cin >> x >> y;

    int unit_price = y / x;
    int payment = 5 * unit_price;

    std::cout << payment << std::endl;

    return 0;
}    
/**************************************************************
	Problem: 1417
	User: fuyijun
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/