#include <bits/stdc++.h>
using namespace std;
int n, m, x, y;
int main() {
  cin >> n >> m >> x >> y;
  for (int i = x; i <= n; i++) {
    printf("%d %d\n", i, y);
    int maxx = 0;
    for (int j = 1; j <= m; j++) {
      if (j == y)
        continue;
      else
        printf("%d %d\n", i, j);
      maxx = j;
    }
    y = maxx;
  }
  for (int i = x - 1; i >= 1; i--) {
    printf("%d %d\n", i, y);
    int maxx = 0;
    for (int j = 1; j <= m; j++) {
      if (j == y)
        continue;
      else
        printf("%d %d\n", i, j);
      maxx = j;
    }
    y = maxx;
  }
}
