#include <bits/stdc++.h>
using namespace std;
const int N = 105;
int n, m, x, y, vis[N][N];
int main() {
  scanf("%d%d%d%d", &n, &m, &x, &y);
  printf("%d %d\n", x, y);
  vis[x][y] = 1;
  for (int i = 1; i <= n; i++) {
    int lv = y;
    printf("%d %d\n", i, y);
    vis[i][y] = 1;
    if (y != m) {
      for (int j = 1; j <= m; j++)
        if (!vis[i][j]) {
          vis[i][j] = 1;
          printf("%d %d\n", i, j);
          lv = j;
        }
    } else {
      for (int j = m; j >= 1; j--)
        if (!vis[i][j]) {
          vis[i][j] = 1;
          printf("%d %d\n", i, j);
          lv = j;
        }
    }
    y = lv;
  }
  return 0;
}
