#include <bits/stdc++.h>
using namespace std;
const long long INF = 1000000007;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t = 1;
  while (t--) {
    int n, m, sx, sz;
    cin >> n >> m >> sx >> sz;
    int x, y;
    x = sx;
    y = sz;
    for (int i = y; i <= m; i++) cout << x << " " << i << "\n";
    for (int i = y - 1; i >= 1; i--) cout << x << " " << i << "\n";
    y = 1;
    for (int i = x + 1; i <= n; i++) {
      if (y == 1) {
        for (int j = y; j <= m; j++) cout << i << " " << j << "\n";
        y = m;
      } else {
        for (int j = m; j >= 1; j--) cout << i << " " << j << "\n";
        y = 1;
      }
    }
    for (int i = 1; i <= x - 1; i++) {
      if (y == 1) {
        for (int j = y; j <= m; j++) cout << i << " " << j << "\n";
        y = m;
      } else {
        for (int j = m; j >= 1; j--) cout << i << " " << j << "\n";
        y = 1;
      }
    }
  }
  return 0;
}
