#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  int x0 = x;
  int y0 = y;
  vector<vector<int>> A;
  A.push_back({x, y});
  x = 1;
  A.push_back({x, y});
  y = 1;
  int D = 1;
  while ((1 <= y) && (y <= m)) {
    if (y != y0) A.push_back({x, y});
    y += D;
  }
  x++;
  while (x <= n) {
    if (y > m) {
      y = m;
      D = -1;
    } else {
      y = 1;
      D = 1;
    }
    while ((1 <= y) && (y <= m)) {
      if (!((x == x0) && (y == y0))) A.push_back({x, y});
      y += D;
    }
    x++;
  }
  for (auto AA : A) cout << AA.at(0) << ' ' << AA.at(1) << endl;
  return 0;
}
