#include <bits/stdc++.h>
using namespace std;
void solve();
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  int t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
void solve() {
  int n, m, sx, sy;
  cin >> n >> m >> sx >> sy;
  int t = n * m;
  int x, y;
  x = sx, y = sy;
  for (int i = 0; i < m; i++) {
    cout << x << " " << y << ("\n");
    if (x == sx && y <= sy && y != 1)
      y--;
    else if (x == sx && y == 1)
      y = sy + 1;
    else if (x == sx && y != m)
      y++;
  }
  x--;
  t = m * (sx - 1);
  for (int i = 0; i < t; i++) {
    cout << x << " " << y << ("\n");
    if ((y == 1 && (sx - x) % 2 == 1) || (y == m && (sx - x) % 2 == 0)) {
      x--;
    } else if (y > 1 && (sx - x) % 2 == 1) {
      y--;
    } else if (y < m && (sx - x) % 2 == 0) {
      y++;
    }
  }
  x = sx + 1;
  t = m * (n - sx);
  if (y == m) {
    for (int i = 0; i < t; i++) {
      cout << x << " " << y << ("\n");
      if ((y == 1 && (x - sx) % 2 == 1) || (y == m && (x - sx) % 2 == 0)) {
        x++;
      } else if (y > 1 && (x - sx) % 2 == 1) {
        y--;
      } else if (y < m && (x - sx) % 2 == 0) {
        y++;
      }
    }
  } else if (y == 1) {
    for (int i = 0; i < t; i++) {
      cout << x << " " << y << ("\n");
      if ((y == m && (x - sx) % 2 == 1) || (y == 1 && (x - sx) % 2 == 0)) {
        x++;
      } else if (y < m && (x - sx) % 2 == 1) {
        y++;
      } else if (y > 1 && (x - sx) % 2 == 0) {
        y--;
      }
    }
  }
}
