#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, i, m, k, q, q1, j;
  long long int x, y;
  cin >> n >> m >> x >> y;
  long long int arr[n + 1][m + 1];
  for (i = 1; i <= n; i++) {
    for (j = 1; j <= m; j++) {
      arr[i][j] = 0;
    }
  }
  long long int l = 1;
  for (i = x; i >= 1; i--) {
    arr[i][y] = l;
    cout << i << " " << y << '\n';
    l++;
  }
  long long int g;
  for (k = 1; k <= n; k++) {
    for (i = y; i >= 1; i--) {
      if (arr[k][i] == 0) {
        arr[k][i] = l;
        cout << k << " " << i << '\n';
        l++;
        g = i;
      }
    }
    for (i = y; i <= m; i++) {
      if (arr[k][i] == 0) {
        arr[k][i] = l;
        cout << k << " " << i << '\n';
        l++;
        g = i;
      }
    }
    y = g;
  }
}
