#include <bits/stdc++.h>
using namespace std;
void solve() {
  int i, j;
  int r, c, x, y;
  cin >> r >> c >> x >> y;
  for (j = y; j <= c; j++) {
    printf("%d %d\n", x, j);
  }
  for (j = y - 1; j > 0; j--) {
    printf("%d %d\n", x, j);
  }
  int swap = 1;
  for (int i = x + 1; i <= r; ++i) {
    if (swap) {
      for (int j = 1; j <= c; ++j) {
        printf("%d %d\n", i, j);
      }
    } else {
      for (int j = c; j > 0; --j) {
        printf("%d %d\n", i, j);
      }
    }
    swap ^= 1;
  }
  for (int i = x - 1; i > 0; --i) {
    if (swap) {
      for (int j = 1; j <= c; ++j) {
        printf("%d %d\n", i, j);
      }
    } else {
      for (int j = c; j > 0; --j) {
        printf("%d %d\n", i, j);
      }
    }
    swap ^= 1;
  }
}
int main() {
  int T = 1;
  while (T--) {
    solve();
  }
}
