#include <bits/stdc++.h>
using namespace std;
int GCD(int x, int y) { return y ? GCD(y, x % y) : x; }
const int INF = 1 << 30;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int sx, sy, n, m;
  cin >> n >> m >> sx >> sy;
  auto print = [&](int x, int y) { cout << x << " " << y << endl; };
  auto dorow = [&](int x, int y) {
    int rc[m + 1], cnt = m - 2;
    memset(rc, 0, sizeof(rc));
    print(x, y);
    rc[y] = 1;
    y = 1;
    rc[y] = 1;
    print(x, y);
    while (cnt) {
      while (rc[y]) y++;
      rc[y] = 1;
      print(x, y);
      cnt--;
    }
    return y;
  };
  int rr[n + 1], cnt = n;
  memset(rr, 0, sizeof(rr));
  while (cnt) {
    rr[sx] = 1;
    sy = dorow(sx, sy);
    sx = 1;
    while (rr[sx]) sx++;
    cnt--;
  }
  return 0;
}
