import java.util.Scanner;

public class Study01 {
	public static void main(String[] args) {
		int i;
		Scanner sc = new Scanner(System.in);
		String A = sc.nextLine();
		String[] K = A.split(" ",0);
		long[] B = new long[4];
		for(i=0;i<4;i++){
			B[i] = Long.parseLong(K[i]);
		}
		//System.out.println((B[0]*B[1]*B[2])%B[3]);
		Long a = B[0]*B[1]%B[3]*B[2];
		System.out.println(a%B[3]);
	}
}