#include <bits/stdc++.h>
using namespace std;
bool mark[110][110];
int main() {
  int n, m, x0, y0;
  cin >> n >> m >> x0 >> y0;
  int x = x0, y = y0;
  while (y >= 1) {
    if (!mark[x][y]) cout << x << " " << y << endl;
    mark[x][y] = true;
    y--;
  }
  y++;
  while (x >= 1) {
    if (!mark[x][y]) cout << x << " " << y << endl;
    mark[x][y] = true;
    x--;
  }
  x++;
  bool flag = true;
  while (y <= m) {
    if (flag) {
      while (x <= n) {
        if (!mark[x][y]) cout << x << " " << y << endl;
        x++;
      }
      x--;
    } else {
      while (x >= 1) {
        if (!mark[x][y]) cout << x << " " << y << endl;
        x--;
      }
      x++;
    }
    y++;
    flag = !flag;
  }
  return 0;
}
