#include <bits/stdc++.h>
using namespace std;
int n, a[1010], b[1010], cnt, x[1010], y[1010], z[1010], w[1010];
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) scanf("%d", &a[i]);
  for (int i = 1; i <= n; ++i) scanf("%d", &b[i]);
  for (int i = 1; i <= n; ++i) {
    if (a[i] == i && b[i] == i) continue;
    ++cnt;
    for (int j = i; j <= n; ++j)
      if (a[j] == i) x[cnt] = j, y[cnt] = i, swap(a[j], a[i]);
    for (int j = i; j <= n; ++j)
      if (b[j] == i) z[cnt] = i, w[cnt] = j, swap(b[j], b[i]);
  }
  printf("%d\n", cnt);
  for (int i = 1; i <= cnt; ++i)
    printf("%d %d %d %d\n", x[i], y[i], z[i], w[i]);
  return 0;
}
