#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <utility>
#include <stack>
#include <functional>
#include <queue>
#include <cmath>
#include <set>
#include <map>

#define rep(i,j,k) for(int i=(int)j;i<(int)k;i++)
#define Sort(x) sort((x).begin(),(x).end())
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define vi vector<int>
#define INF (int)1e9
#define INFL 1e18
#define MOD 1e9+7
#define pb push_back
#define MP make_pair
typedef long long int ll;
typedef std::pair<int,int> pii;
int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};

int temp[3]={1,5,10};

using namespace std;

int main() {
    ll h,w,n,k;
    cin>>h>>w>>n>>k;
    ll sum=h*w;
    if(sum%n==0){
        if(k==n)cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
    }else{
        if(k==sum%n)cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
    }
    
    return 0;
}