#include <bits/stdc++.h>
using namespace std;
int n, m, x, y;
inline int read() {
  int s = 0, w = 1;
  char ch = getchar();
  while (ch > '9' || ch < '0') {
    if (ch == '-') w = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    s = s * 10 + ch - '0';
    ch = getchar();
  }
  return s * w;
}
int main() {
  cin.tie(0);
  cin >> n >> m >> x >> y;
  cout << x << ' ' << y << endl;
  int t = m;
  if (y == 1)
    t = 1;
  else if (y == m)
    t = m;
  if (t == 1) {
    for (int i = 2; i <= m; i++) cout << x << ' ' << i << endl;
  } else {
    for (int i = m; i >= 1; i--) {
      if (i != y) cout << x << ' ' << i << endl;
    }
  }
  for (int i = 1; i <= n; i++) {
    if (i == x) continue;
    if (t == m) {
      for (int j = 1; j <= m; j++) cout << i << ' ' << j << endl;
      t = 1;
    } else {
      for (int j = m; j >= 1; j--) cout << i << ' ' << j << endl;
      t = m;
    }
  }
  return 0;
}
