#include <bits/stdc++.h>
using namespace std;
long long mod = 1000000007;
template <typename T>
void debug(vector<T> x) {
  for (auto e : x) {
    cout << e << " ";
  }
  cout << "\n";
}
void solve() {
  long long n, m, x, y;
  cin >> n >> m >> x >> y;
  vector<pair<long long, long long>> ans;
  stack<pair<long long, long long>> st;
  long long mat[n + 1][m + 1];
  for (long long i = 1; i <= n; i++)
    for (long long j = 1; j <= m; j++) mat[i][j] = 0;
  st.push({x, y});
  while (!st.empty()) {
    pair<long long, long long> cur = st.top();
    if (mat[cur.first][cur.second] == 0) {
      mat[cur.first][cur.second] = 1;
      ans.push_back({cur.first, cur.second});
    }
    st.pop();
    for (long long i = 1; i <= n; i++) {
      if (mat[i][cur.second] == 0) {
        st.push({i, cur.second});
      }
    }
    for (long long j = 1; j <= m; j++) {
      if (mat[cur.first][j] == 0) {
        st.push({cur.first, j});
      }
    }
  }
  for (auto x : ans) {
    cout << x.first << " " << x.second << "\n";
  }
}
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
