#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
int cmp(const void *a,const void *b){
    if(*(int*)a>*(int*)b){return 1;}
    else if(*(int*)a<*(int*)b){return -1;}
    else {return 0;}
}
int min(int a,int b){

    if(a>=b){return b;}
    return a;
}
//cww
int main(void){
long long int a,b,c,d;
int res;
scanf("%lld %lld %lld %lld",&a,&b,&c,&d);
    res=a*b%d;
    res=res*c%d;
    printf("%d\n",res);
}