#include <bits/stdc++.h>
using namespace std;
int matrix[200][200];
int main() {
  int n, m, sx, sy;
  cin >> n >> m >> sx >> sy;
  matrix[sx][sy] = 1;
  cout << sx << ' ' << sy << endl;
  matrix[sx][1] = 1;
  for (int i = sx; i >= 1; i--) {
    if ((sx - i) % 2 == 0) {
      cout << i << ' ' << 1 << endl;
      for (int j = 2; j <= m; j++) {
        if (i == sx) {
          if (j != sy) cout << i << ' ' << j << endl;
        } else {
          cout << i << ' ' << j << endl;
        }
      }
    } else {
      cout << i << ' ' << m << endl;
      for (int j = m - 1; j >= 1; j--) {
        if (i == sx) {
          if (j != sy) cout << i << ' ' << j << endl;
        } else {
          cout << i << ' ' << j << endl;
        }
      }
    }
  }
  if ((sx - 1) % 2 == 0) {
    for (int j = sx + 1; j <= n; j++) {
      if ((j - sx) % 2 == 1) {
        cout << j << ' ' << m << endl;
        for (int k = m - 1; k >= 1; k--) {
          cout << j << ' ' << k << endl;
        }
      } else {
        cout << j << ' ' << 1 << endl;
        for (int k = 2; k <= m; k++) {
          cout << j << ' ' << k << endl;
        }
      }
    }
  } else {
    for (int j = sx + 1; j <= n; j++) {
      if ((j - sx) % 2 != 1) {
        cout << j << ' ' << m << endl;
        for (int k = m - 1; k >= 1; k--) {
          cout << j << ' ' << k << endl;
        }
      } else {
        cout << j << ' ' << 1 << endl;
        for (int k = 2; k <= m; k++) {
          cout << j << ' ' << k << endl;
        }
      }
    }
  }
  return 0;
}
