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