#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, m, sx, sy;
  cin >> n >> m >> sx >> sy;
  int cnt = n * m;
  int visited[105][105] = {0};
  for (int i = sx, j = sy; i >= 1; i--) {
    visited[i][j] = 1;
    cout << i << " " << j << endl;
  }
  for (int i = 1, j = sy - 1; j >= 1; j--) {
    visited[i][j] = 1;
    cout << i << " " << j << endl;
  }
  for (int i = 1; i <= n; i++) {
    if (i % 2 != 0) {
      for (int j = 1; j <= m; j++) {
        if (!(visited[i][j] == 1)) cout << i << " " << j << endl;
      }
    } else {
      for (int j = m; j >= 1; j--) {
        if (!(visited[i][j] == 1)) cout << i << " " << j << endl;
      }
    }
  }
  return 0;
}
