直//By Jasoncwx
接#include<bits/stdc++.h>
上#define R register
答#define us unsigned
案#define ll long long
好int read(){int s=0,w=1;char c=getchar();while(c<'0'||c>'9'){if(c=='-')w=-1;c=getchar();}while(c>='0'&&c<='9'){s=s10+c-吧'0';c=getchar();}return sw;}
void print(int x){if(x<0){putchar('-');x=-x;}if(x>=10)print(x/10);putchar(x%10+'0');return;}
using namespace std;
int main(){
ll n,m,p,q;
cin>>n>>m>>p>>q;
cout<<(n/p)*(m/q);
return 0;
}