#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long n, m, x, y;
  cin >> n >> m >> x >> y;
  long a[n][m];
  for (long i = x; i >= 1; i--) {
    std::cout << i << " " << y << std::endl;
    a[i - 1][y - 1] = 0;
  }
  for (long i = y + 1; i <= m; i++) {
    std::cout << 1 << " " << i << std::endl;
    a[0][i - 1] = 0;
  }
  for (long i = y - 1; i >= 1; i--) {
    std::cout << 1 << " " << i << std::endl;
    a[0][i - 1] = 0;
  }
  long j = 1;
  for (long i = 2; i <= n; i++) {
    if (j <= 1) {
      for (j = 1; j <= m; j++)
        if (j != y) {
          cout << i << " " << j << endl;
        } else if (i > x)
          cout << i << " " << j << endl;
    } else if (j >= m) {
      for (j = m; j >= 1; j--) {
        if (j != y) {
          cout << i << " " << j << endl;
        } else if (i > x)
          cout << i << " " << j << endl;
      }
    }
  }
  return 0;
}
