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