#include <bits/stdc++.h>
using namespace std;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
long long fpow(long long a, long long i) {
  if (i < 0) return 0;
  if (i == 0) return 1;
  long long temp = fpow(a, i >> 1);
  temp = temp * temp % 998244353;
  if (i & 1) temp = (long long)temp * a % 998244353;
  return temp % 998244353;
}
long long cmp2(long long i, long long j) { return j < i; }
long long pair_cmp2(pair<int, int> a, pair<int, int> b) {
  if (a.first < b.first) return 1;
  if (a.second < b.second && a.first == b.first) return 1;
  return 0;
}
signed main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  ;
  long long n, m, a, b;
  cin >> n >> m >> a >> b;
  vector<int> line(n + 1);
  for (int i = 1; i <= n; i++) line[i] = i;
  line[a] = 1;
  ;
  int end;
  for (int i = b; i >= 1; i--) {
    cout << a << " " << i << endl;
    end = i;
  }
  for (int i = b + 1; i <= m; i++) {
    cout << a << " " << i << endl;
    end = i;
  }
  for (int i = 2; i <= n; i++) {
    if (end == m) {
      for (int j = m; j >= 1; j--) cout << line[i] << " " << j << endl;
      end = 1;
    } else {
      for (int j = 1; j <= m; j++) cout << line[i] << " " << j << endl;
      end = m;
    }
  }
  return 0;
}
