#include <bits/stdc++.h>
using namespace std;
long long fact[1000001], power[1000001];
long long powerr(long long x, long long y);
long long mpower(long long x, long long y, long long p);
long long gcdExtended(long long a, long long b);
bool isPrime(long long n);
long long func(long long n) {
  long long x = sqrt(n);
  if (n % x == 0) x = x + 1;
  long long i;
  for (i = 2; i < n / 2; i++) {
    if (n % i == 0 && isPrime(i) == true) {
      return i;
    }
  }
  return n;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t, j, k, l, h, p, q, r, x, i, y, z, a, b, c, d, f, n, m,
      M = 1000000007;
  char ch, ch2, ch3;
  string s1, s2, s3;
  vector<long long> v, w;
  set<long long> S;
  t = 1;
  while (t--) {
    cin >> n >> m >> x >> y;
    cout << x << " " << y;
    cout << "\n";
    z = 0;
    for (j = x - 1; j < n; j++) {
      if (z == 0) {
        for (k = z; k < m; k++) {
          if (j == x - 1 && k == y - 1)
            continue;
          else {
            cout << j + 1 << " " << k + 1;
            cout << "\n";
          }
        }
        z = m - 1;
      } else {
        for (k = m - 1; k >= 0; k--) {
          if (j == x - 1 && k == y - 1)
            continue;
          else {
            cout << j + 1 << " " << k + 1;
            cout << "\n";
          }
        }
        z = 0;
      }
    }
    for (j = x - 2; j >= 0; j--) {
      if (z == 0) {
        for (k = z; k < m; k++) {
          if (j == x - 1 && k == y - 1)
            continue;
          else {
            cout << j + 1 << " " << k + 1;
            cout << "\n";
          }
        }
        z = m - 1;
      } else {
        for (k = m - 1; k >= 0; k--) {
          if (j == x - 1 && k == y - 1)
            continue;
          else {
            cout << j + 1 << " " << k + 1;
            cout << "\n";
          }
        }
        z = 0;
      }
    }
  }
}
long long gcdExtended(long long a, long long b) {
  if (b == 0) {
    return a;
  } else
    return gcdExtended(b, a % b);
}
long long mpower(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long powerr(long long x, long long y) {
  long long res = 1;
  while (y > 0) {
    if (y & 1) res = res * x;
    y = y >> 1;
    x = x * x;
  }
  return res;
}
bool isPrime(long long n) {
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  long long p = sqrt(n);
  for (int i = 5; i <= p; i = i + 6)
    if (n % i == 0 || n % (i + 2) == 0) return false;
  return true;
}
