#include <bits/stdc++.h>
using namespace std;
bool vis[110][110];
void solve() {
  int n = 0, k = 0, ans = 0, r = 0, m = 0, x = 0, y = 0, z = 0;
  cin >> n >> m;
  memset(vis, 0, sizeof vis);
  cin >> x >> y;
  vis[x][y] = 1;
  cout << x << " " << y << "\n";
  cout << x << " " << 1 << "\n";
  vis[x][1] = 1;
  for (int i = 1; i <= m; i++) {
    if (i % 2) {
      for (int j = 1; j <= n; j++) {
        if (!vis[j][i]) {
          cout << j << " " << i << "\n";
        }
      }
    } else {
      for (int j = n; j >= 1; j--) {
        if (!vis[j][i]) {
          cout << j << " " << i << "\n";
        }
      }
    }
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
