#include <bits/stdc++.h>
using namespace std;
double EPS = 1e-9;
int INF = 100005;
long long int mod = 1000000007;
long long TES = 1000007;
long long INFF = 1000000000000000005LL;
double PI = acos(-1);
int dirx[8] = {-1, 0, 0, 1, -1, -1, 1, 1};
int diry[8] = {0, 1, -1, 0, -1, 1, -1, 1};
void solve() {
  int n, m, p, q;
  cin >> n >> m >> p >> q;
  cout << p << " " << q << endl;
  if (q == 1) {
    bool flag = true;
    for (int i = p; i <= n; i++) {
      if (flag) {
        for (int j = q; j <= m; j++) {
          if (i == p && j == q)
            continue;
          else
            ;
          cout << i << " " << j << endl;
        }
        flag = false;
      } else {
        for (int j = m; j >= q; j--) {
          cout << i << " " << j << endl;
        }
        flag = true;
      }
    }
    for (int i = 1; i < p; i++) {
      if (flag) {
        for (int j = q; j <= m; j++) {
          cout << i << " " << j << endl;
        }
        flag = false;
      } else {
        for (int j = m; j >= p; j--) {
          cout << i << " " << j << endl;
        }
        flag = true;
      }
    }
  } else {
    bool flag = false;
    for (int i = p; i <= n; i++) {
      if (flag) {
        for (int j = 1; j <= m; j++) {
          if (i == p && j == q)
            continue;
          else
            ;
          cout << i << " " << j << endl;
        }
        flag = false;
      } else {
        for (int j = m; j >= 1; j--) {
          if (i == p && j == q)
            continue;
          else
            cout << i << " " << j << endl;
        }
        flag = true;
      }
    }
    for (int i = 1; i < p; i++) {
      if (flag) {
        for (int j = 1; j <= m; j++) {
          if (i == p && j == q)
            continue;
          else
            cout << i << " " << j << endl;
        }
        flag = false;
      } else {
        for (int j = m; j >= 1; j--) {
          if (i == p && j == q)
            continue;
          else
            cout << i << " " << j << endl;
        }
        flag = true;
      }
    }
  }
  return;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  ;
  solve();
  return 0;
}
