#include <bits/stdc++.h>
const int LG = 21;
const int FN = 400005;
const long long MOD = 924844033;
const long long INF = 1e9;
const long long INFLL = 1e18;
using namespace std;
int cx[4] = {-1, 0, 1, 0};
int cy[4] = {0, -1, 0, 1};
long long inq(long long x, long long y) {
  if (!y) return 1 % MOD;
  long long l = inq(x, y / 2);
  if (y % 2) return l * l % MOD * x % MOD;
  return l * l % MOD;
}
long long rev(long long x) { return inq(x, MOD - 2); }
bool __precomputed_combinatorics = 0;
vector<long long> __fact, __ufact, __rev;
void __precompute_combinatorics() {
  __precomputed_combinatorics = 1;
  __fact.resize(FN);
  __ufact.resize(FN);
  __rev.resize(FN);
  __rev[1] = 1;
  for (int i = 2; i < FN; i++)
    __rev[i] = MOD - __rev[MOD % i] * (MOD / i) % MOD;
  __fact[0] = 1, __ufact[0] = 1;
  for (int i = 1; i < FN; i++)
    __fact[i] = __fact[i - 1] * i % MOD,
    __ufact[i] = __ufact[i - 1] * __rev[i] % MOD;
}
long long fact(int x) {
  if (!__precomputed_combinatorics) __precompute_combinatorics();
  return __fact[x];
}
long long cnk(int n, int k) {
  if (!__precomputed_combinatorics) __precompute_combinatorics();
  return __fact[n] * __ufact[n - k] % MOD * __ufact[k] % MOD;
}
const int N = 2020;
int n, k;
int r[N], c[N], pr[N], pc[N];
struct answer {
  int x1, y1, x2, y2;
};
bool boring(answer a) { return a.x1 == a.x2 && a.y1 == a.y2; }
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> r[i], r[i]--;
    pr[r[i]] = i;
  }
  for (int i = 0; i < n; i++) {
    cin >> c[i], c[i]--;
    pc[c[i]] = i;
  }
  vector<answer> ans;
  for (int i = 0; i < n; i++) {
    int R = pr[i], C = pc[i];
    answer a;
    a.x1 = i, a.y1 = C, a.x2 = R, a.y2 = i;
    swap(r[R], r[i]);
    swap(c[C], c[i]);
    pc[c[C]] = C;
    pc[c[i]] = i;
    pr[r[R]] = R;
    pr[r[i]] = i;
    if (!boring(a)) ans.push_back(a);
  }
  cout << ans.size() << "\n";
  for (int i = 0; i < ans.size(); i++) {
    cout << ans[i].x1 + 1 << " " << ans[i].y1 + 1 << " " << ans[i].x2 + 1 << " "
         << ans[i].y2 + 1 << "\n";
  }
}
