#include <bits/stdc++.h>
using namespace std;
long long gcd(long long x, long long y) {
  if (x == 0) return y;
  return gcd(y % x, x);
}
long long powmod(long long x, long long y, long long m) {
  if (y == 0) return 1;
  long long p = powmod(x, y / 2, m) % m;
  p = (p * p) % m;
  return (y % 2 == 0) ? p : (x * p) % m;
}
long long modif(long long x, long long m) { return (powmod(x, m - 2, m)); }
bool fa(vector<long long> &x, vector<long long> &y) { return x[0] < y[0]; }
bool fa1(vector<long long> &x, vector<long long> &y) { return x[1] < y[1]; }
bool f1(pair<long long, long long> &x, pair<long long, long long> &y) {
  return x.second > y.second;
}
bool f2(pair<long long, long long> &x, pair<long long, long long> &y) {
  return x.first > y.first;
}
bool f3(long long &x, long long &y) { return x > y; }
const long long maxn = 2e5 + 2;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n, m, sx, sy;
  cin >> n >> m >> sx >> sy;
  std::vector<pair<long long, long long> > k;
  k.push_back(make_pair(sx, sy));
  long long it = 0;
  long long ch = 0;
  while (it != k.size()) {
    long long x = k[it].first, y = k[it].second;
    if (x == sx && ch != 0) break;
    ch++;
    cout << x << " " << y << "\n";
    long long l = y;
    for (int i = 1; i < m + 1; i++) {
      if (i != y) {
        cout << x << " " << i << "\n";
        l = i;
      }
    }
    if (x == n) {
      k.push_back(make_pair(1, l));
    } else {
      k.push_back(make_pair(x + 1, l));
    }
    it++;
  }
  return 0;
}
