#include <stdio.h>
int main(void){
    long int A,B,C,D;
    long int ans;

    scanf("%ld %ld %ld %ld",&A,&B,&C,&D);

    ans = (((A%D)*(B%D))%D)*(C%D);
    ans = ans%D;

    printf("%ld\n",ans);

    return 0;
}