#include <iostream>

int main(void) {
    int a = 0,b = 0,c = 0,d = 0;
    int rem = 0;
    std::cin >> a >> b >> c >> d;
    rem = (a % d) * (b % d) * (c % d);
    rem = rem % d;
    std::cout << rem << std::endl;
    return 0;
}