#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int T;
  T = 1;
  for (int t = 0; t < T; ++t) {
    int n, m;
    cin >> n >> m;
    vector<vector<int> > v(n, vector<int>(m, 0));
    int x, y;
    cin >> x >> y;
    int cx = x - 1, cy = y - 1;
    v[cx][cy] = 1;
    v[0][cy] = 1;
    v[0][0] = 1;
    cout << cx + 1 << " " << cy + 1 << "\n";
    cout << 1 << " " << cy + 1 << "\n";
    cout << 1 << " " << 1 << "\n";
    int i = 0, j = 0, c = 1, sum = 3;
    ;
    while (sum != m * n) {
      if (v[i][j] != 1) {
        cout << i + 1 << " " << j + 1 << "\n";
        sum++;
      }
      j += c;
      if (j == m || j == -1) {
        j -= c;
        c *= -1;
        i++;
      }
    }
  }
}
