#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int T = 1;
  for (int t = 1; t <= T; t++) {
    int n, m, x, y;
    cin >> n >> m >> x >> y;
    vector<vector<int> > vec(n + 1, vector<int>(m + 1, 0));
    vec[x][y] = 1;
    cout << x << " " << y << "\n";
    int tempy = y;
    while (y > 1) {
      cout << x << " " << y - 1 << endl;
      y--;
    }
    y = tempy;
    while (y < m) {
      cout << x << " " << y + 1 << endl;
      y++;
    }
    bool left = true;
    int tempx = x;
    while (x > 1) {
      x--;
      if (left) {
        while (y >= 1) {
          cout << x << " " << y << endl;
          y--;
        }
        y = 1;
        left = false;
      } else {
        while (y <= m) {
          cout << x << " " << y << endl;
          y++;
        }
        y = m;
        left = true;
      }
    }
    x = tempx + 1;
    while (x <= n) {
      if (left) {
        while (y >= 1) {
          cout << x << " " << y << endl;
          y--;
        }
        y = 1;
        left = false;
      } else {
        while (y <= m) {
          cout << x << " " << y << endl;
          y++;
        }
        y = m;
        left = true;
      }
      x++;
    }
  }
  return 0;
}
