#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define INPUT(str) do{char *p;fgets(str,sizeof(str),stdin);p=strchr(str,'\n');if(p)*p='\0';}while(0)
int main() {
	char	str[10*4+3];
	long	a,b,c,d;

    INPUT( str );
	sscanf( str,"%ld %ld %ld %ld", &a, &b, &c, &d );
	a %= d;
	b %= d;
	c %= d;
	a = ( a * b )% d;
	a = ( a * c ) % d;
	printf("%ld\n", a);
}