// long long int 未使用版

#include <stdio.h>

int m(int x, int y, int r) {
	int e = 1 << 15;
	int a = x / e, b = x % e;
	int c = y / e, d = y % e;
	
	int X = a * c % r;
	int Y = (a * d + b * c) % r;
	int Z = b * d % r;
	
	for(int i = 0; i < 15; i++) {
		X *= 2; X %= r;
		X *= 2; X %= r;
		Y *= 2; Y %= r;
	}
	
	return ((X + Y) % r + Z) % r;
}

int main() {
	unsigned int a, b, c, d;
	scanf("%u%u%u%u", &a, &b, &c, &d);
	
	printf("%d\n", m( m(a, b, d), c, d) );
	
	return 0;
}