#include <iostream>
using namespace std;
int H, W, A, B, ans = 0;
void dfs(int i, int bit, int A, int B){
    if(i == H * W) return (void)ans++;
    if(bit & 1 << i) return dfs(i + 1, bit, A, B);
    if(B) dfs(i + 1, bit | 1 << i, A, B - 1);
    if(A){
        if(i % W != W - 1 && ~bit & 1 << (i + 1)) dfs(i + 1, bit | 1 << i | 1 << (i + 1), A - 1, B);
        if(i + W < H * W) dfs(i + 1, bit | 1 << i | 1 << (i + W), A - 1, B);
    }
}
int main(){
    cin >> H >> W >> A >> B;
    dfs(0, 0, A, B);
    cout << ans << endl;
}
#include<bits/stdc++.h>
using namespace std;
main()
{
	float v,t,s,d;
	cin>>v>>t>>s>>d;
	 float app=d/v;
	 if(app<t||app>s)
	 {
	 	cout<<"Yes"<<endl;
	 }
	 else
	 {
	 	cout<<"No"<<endl;
	 }
}