#include <bits/stdc++.h>
using namespace std;
int main() {
  int tc;
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  int visit[105][105] = {0};
  cout << x << " " << y << "\n";
  visit[x][y] = 1;
  for (int i = x - 1; i >= 1; --i) {
    cout << i << " " << y << "\n";
    visit[i][y] = 1;
    if (i == 1) {
      break;
    }
  }
  for (int i = 1; i <= n; ++i) {
    int j;
    if (i % 2 == 0)
      j = m;
    else
      j = 1;
    if (j == 1) {
      for (; j <= m; ++j) {
        if (visit[i][j] == 0) {
          cout << i << " " << j << "\n";
        }
      }
    } else {
      for (; j >= 1; --j) {
        if (visit[i][j] == 0) {
          cout << i << " " << j << "\n";
        }
      }
    }
  }
  return 0;
}
