#include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <functional>
#include <queue>
#include <stack>
#include <cmath>
#include <iomanip>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define CLR(a) memset((a), 0 ,sizeof(a))
#define MCLR(a) memset((a), -1 ,sizeof(a))
#define SZ(a) (sizeof(a))
#define FILL(a,v) fill((int*)a,(int*)(a+(SZ(a)/SZ(*(a)))),v)

bool cheak(int x, int y, int xMax, int yMax)
{
	return x >= 0 && y >= 0 && xMax > x && yMax > y;
}
const int dx[4] = { -1, 0, 1, 0 }, dy[4] = { 0, 1, 0, -1 };
const int INF = 2147483647;
typedef pair<int, int> P;
typedef long long ll;
typedef unsigned long long ull;
const int mod = 1000000007;


int main()
{
	ull h, w, n, k;
	cin >> h >> w >> n >> k;

	ull sum = h * w;

	if (sum % n == k % n)
		cout << "YES" << endl;
	else
		cout << "NO" << endl;

	return 0;
}