#include <bits/stdc++.h>
using namespace std;
bool viz[105][105];
int dx[4] = {0, 1, 0, -1};
int dy[4] = {1, 0, -1, 0};
int main() {
  cin.tie(0)->sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  int T = 1;
  while (T--) {
    int n, m, x, y;
    cin >> n >> m >> x >> y;
    vector<pair<int, int> > sol;
    viz[x][y] = 1;
    cout << x << " " << y << '\n';
    int cnt = 1;
    for (int j = 1; j <= m; j++) {
      if (j != y) {
        cout << x << " " << j << '\n';
      }
    }
    for (int i = x + 1; i <= n; i++) {
      if (cnt % 2 == 1) {
        for (int j = m; j >= 1; j--) {
          cout << i << " " << j << '\n';
        }
      } else {
        for (int j = 1; j <= m; j++) {
          cout << i << " " << j << '\n';
        }
      }
      cnt++;
    }
    for (int i = x - 1; i >= 1; i--) {
      if (cnt % 2 == 1) {
        for (int j = m; j >= 1; j--) {
          cout << i << " " << j << '\n';
        }
      } else {
        for (int j = 1; j <= m; j++) {
          cout << i << " " << j << '\n';
        }
      }
      cnt++;
    }
  }
}
