#include <bits/stdc++.h>
using ll = long long;
using namespace std;
int vis[105][105];
int main() {
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << endl;
  cout << 1 << " " << y << endl;
  vis[x][y] = vis[1][y] = 1;
  bool is = 1;
  for (int i = 1; i <= n; i++) {
    if (is) {
      for (int j = 1; j <= m; j++) {
        if (vis[i][j]) continue;
        cout << i << " " << j << endl;
      }
    } else {
      for (int j = m; j > 0; j--) {
        if (vis[i][j]) continue;
        cout << i << " " << j << endl;
      }
    }
    is ^= 1;
  }
  return 0;
}
