#include <bits/stdc++.h>
using namespace std;
const int sz = 2e5 + 5;
int tc, n, m, x, y, vis[105][105];
void dfs(int x, int y) {
  cout << x << " " << y << "\n";
  vis[x][y] = 1;
  for (int i = 1; i <= m; i++) {
    if (!vis[x][i]) {
      dfs(x, i);
      return;
    }
  }
  for (int i = 1; i <= n; i++) {
    if (!vis[i][y]) {
      dfs(i, y);
      return;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0);
  cin >> n >> m >> x >> y;
  dfs(x, y);
  return 0;
}
