#include <bits/stdc++.h>
using namespace std;
int _ = 1, tc = 1;
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
int getmod(int x, int y, int mod) { return (((x - y) % mod) + mod) % mod; }
int MAXN = 46341 + 1;
int spf[46341 + 1];
int d, x, y;
int gcd(int a, int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
void sieve() {
  for (int i = 1; i < MAXN; i++) spf[i] = i;
  for (int i = 4; i < MAXN; i += 2) spf[i] = 2;
  for (int i = 3; i * i < MAXN; i += 2) {
    if (spf[i] == i) {
      for (int j = i * i; j < MAXN; j += i) {
        if (spf[j] == j) spf[j] = i;
      }
    }
  }
}
void extended_gcd(int a, int b) {
  if (b == 0) {
    d = a;
    x = 1;
    y = 0;
  } else {
    extended_gcd(b, a % b);
    int temp = y;
    y = x - y * (a / b);
    x = temp;
  }
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long lcm(long long a, long long b) { return (a * b) / gcd(a, b); }
void solve() {
  long long n, m, s1, s2;
  cin >> n >> m >> s1 >> s2;
  cout << s1 << " " << s2 << endl;
  for (int i = 1; i <= m; i++) {
    if (i == s2) continue;
    cout << s1 << " " << i << endl;
  }
  int curr = m, new_curr = m;
  for (int i = s1 - 1; i >= 1; i--) {
    if (curr == m) {
      for (int j = m; j > 0; j--) {
        cout << i << " " << j << endl;
      }
      curr = 1;
    } else {
      for (int j = 1; j <= m; j++) {
        cout << i << " " << j << endl;
      }
      curr = m;
    }
  }
  for (int i = s1 + 1; i <= n; i++) {
    if (curr == m) {
      for (int j = m; j > 0; j--) {
        cout << i << " " << j << endl;
      }
      curr = 1;
    } else {
      for (int j = 1; j <= m; j++) {
        cout << i << " " << j << endl;
      }
      curr = m;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  while (_--) {
    solve();
  }
  return 0;
}
