#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  long long n, m, x, y;
  cin >> n >> m >> x >> y;
  vector<pair<long long, long long>> res;
  for (long long i = x; i <= n; i++) {
    if (i == x) {
      for (long long j = y; j <= m; j++) {
        res.push_back({i, j});
      }
      for (long long j = y - 1; j >= 1; j--) {
        res.push_back({i, j});
      }
    } else if ((i - x) % 2) {
      for (long long j = 1; j <= m; j++) {
        res.push_back({i, j});
      }
    } else if ((i - x) % 2 == 0) {
      for (long long j = m; j >= 1; j--) {
        res.push_back({i, j});
      }
    }
  }
  long long z = n - x;
  for (long long i = x - 1; i >= 1; i--) {
    if (z % 2 == 0) {
      if ((x - i) % 2) {
        for (long long j = 1; j <= m; j++) {
          res.push_back({i, j});
        }
      } else if ((x - i) % 2 == 0) {
        for (long long j = m; j >= 1; j--) {
          res.push_back({i, j});
        }
      }
    } else {
      if ((x - i) % 2 == 0) {
        for (long long j = 1; j <= m; j++) {
          res.push_back({i, j});
        }
      } else if ((x - i) % 2) {
        for (long long j = m; j >= 1; j--) {
          res.push_back({i, j});
        }
      }
    }
  }
  for (auto i : res) cout << i.first << " " << i.second << "\n";
}
