#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pi;
typedef vector<pi> vpi;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<bool> vb;
typedef set<ll> sll;
#define IOS cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(false)
#define INF(dtype) numeric_limits<dtype>::max()
#define NINF(dtype) numeric_limits<dtype>::min()
#define fi first
#define se second
#define pb push_back
typedef vector<vb> vvb;
typedef vector<string> vs;
int main() {
int w, h, k, l;
cin >> w >> h >> k >> l;
int xh, yh, xv, yv;
cin >> xh >> yh >> xv >> yv;
vs g(h);
for(string& gv : g) cin >> gv;
cout << "YES" << endl;
return 0;
}
