#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, m, x, y;
  scanf("%lld%lld%lld%lld", &n, &m, &x, &y);
  cout << x << " " << y << "\n";
  for (int i = 1; i <= n; i++) {
    if (i != x) {
      cout << i << " " << y << "\n";
    }
  }
  int f = 0;
  for (int j = y + 1; j <= m; j++) {
    if (f == 0) {
      for (int i = n; i >= 1; i--) {
        cout << i << " " << j << "\n";
        f = 1;
      }
      continue;
    }
    if (f == 1) {
      for (int i = 1; i <= n; i++) {
        cout << i << " " << j << "\n";
        f = 0;
      }
    }
  }
  if ((m - y) % 2 == 0) {
    f = 0;
    for (int j = 1; j <= y - 1; j++) {
      if (f == 0) {
        for (int i = n; i >= 1; i--) {
          cout << i << " " << j << "\n";
          f = 1;
        }
        continue;
      }
      if (f == 1) {
        for (int i = 1; i <= n; i++) {
          cout << i << " " << j << "\n";
          f = 0;
        }
      }
    }
  } else {
    f = 1;
    for (int j = 1; j <= y - 1; j++) {
      if (f == 0) {
        for (int i = n; i >= 1; i--) {
          cout << i << " " << j << "\n";
          f = 1;
        }
        continue;
      }
      if (f == 1) {
        for (int i = 1; i <= n; i++) {
          cout << i << " " << j << "\n";
          f = 0;
        }
      }
    }
  }
  return 0;
}
