#include <bits/stdc++.h>
using namespace std;
int visited[100][100];
bool isSafe(int i, int j, int row, int col) {
  return i >= 0 and i <= row - 1 and j >= 0 and j <= col - 1 and
         visited[i][j] == 0;
}
void dfs(int i, int j, int row, int col) {
  int rows[4] = {-1, 0, 0, 1};
  int cols[4] = {0, -1, 1, 0};
  visited[i][j] = 1;
  cout << i + 1 << " " << j + 1 << "\n";
  for (int k = 0; k <= 3; k++) {
    if (isSafe(i + rows[k], j + cols[k], row, col)) {
      dfs(i + rows[k], j + cols[k], row, col);
    }
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int row, col, x, y;
  cin >> row >> col >> x >> y;
  dfs(x - 1, y - 1, row, col);
  return 0;
}
