#include <bits/stdc++.h>
using namespace std;
namespace io {
inline int rdi() {
  int v;
  cin >> v;
  return v;
}
inline long long rdll() {
  long long v;
  cin >> v;
  return v;
}
inline string rds() {
  string s;
  cin >> s;
  return s;
}
inline char rdc() {
  char c;
  cin >> c;
  return c;
}
template <class T>
void rdv(T beg_iter, T end_iter) {
  for (; beg_iter != end_iter; ++beg_iter) cin >> *beg_iter;
}
inline void wri(const int v) { cout << v; }
inline void wrll(const long long &v) { cout << v; }
inline void wrs(const string &s) { cout << s; }
inline void wrc(const char c) { cout << c; }
template <class T>
void wrv(T beg_iter, T end_iter, string separator = " ",
         string end_of_line = "\n") {
  for (; beg_iter != end_iter; ++beg_iter) {
    cout << *beg_iter;
    cout << separator;
  }
  cout << end_of_line;
}
}  // namespace io
using namespace io;
bool sortbysec(const pair<long long, long long> &a,
               const pair<long long, long long> &b) {
  return (a.second < b.second);
}
long long binpow(long long a, long long b, long long m) {
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a % m;
    a = a * a % m;
    b >>= 1;
  }
  return res;
}
string path = "DLRU";
vector<int> di = {1, 0, 0, -1};
vector<int> dj = {0, -1, 1, 0};
void solve();
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  int t;
  if (1 == 1) {
    t = 1;
  } else {
    cin >> t;
  }
  while (t--) solve();
  return 0;
}
void solve() {
  long long n, m, sx, sy;
  cin >> n >> m >> sx >> sy;
  for (long long j = sy; j >= 1; --j) cout << sx << " " << j << '\n';
  for (long long i = sx - 1; i >= 1; --i) cout << i << " " << 1 << '\n';
  for (long long i = sx + 1; i < n + 1; ++i) cout << i << " " << 1 << '\n';
  bool up = 1;
  for (long long j = 2; j < m + 1; ++j) {
    if (up) {
      for (long long i = n; i >= 1; --i) {
        if (i == sx && j <= sy) continue;
        cout << i << " " << j << '\n';
      }
      up = 0;
    } else {
      for (long long i = 1; i < n + 1; ++i) {
        if (i == sx && j <= sy) continue;
        cout << i << " " << j << '\n';
      }
      up = 1;
    }
  }
}
