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