#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main(void) {
	long long int A, B, C, D;
	scanf("%lld%lld%lld%lld", &A, &B, &C, &D);
	printf("%lld\n", ((((A % D) * (B  % D)) % D)*(C%D)) % D);
}