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