package chelper;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import io.InputReader;
import io.OutputWriter;

public class I {
  int n;
  int[] a, b;
  Map<Integer, Integer> l1, l2;

  void swap(int i, int j) {
    int p1 = l1.get(a[i]);
    int p2 = l2.get(a[i]);
    if (p1 != i) {
      int c = p1;
      p1 = p2;
      p2 = c;
    }

    int p3 = l1.get(b[j]);
    int p4 = l2.get(b[j]);
    if (p3 != n + j) {
      int c = p3;
      p3 = p4;
      p4 = c;
    }

    l1.put(a[i], n + j);
    l2.put(a[i], p2);

    l1.put(b[j], i);
    l2.put(b[j], p4);

    int c = a[i];
    a[i] = b[j];
    b[j] = c;
  }

  public void solve(int testNumber, InputReader in, OutputWriter out) {
    n = in.nextInt();
    a = in.nextIntArray(n);
    b = in.nextIntArray(n);

    l1 = new HashMap<>();
    l2 = new HashMap<>();

    for (int i = 0; i < n; i++) {
      if (!l1.containsKey(a[i])) {
        l1.put(a[i], i);
      } else {
        l2.put(a[i], i);
      }
    }

    for (int i = 0; i < n; i++) {
      if (!l1.containsKey(b[i])) {
        l1.put(b[i], i + n);
      } else {
        l2.put(b[i], i + n);
      }
    }

    List<String> actions = new ArrayList<>();

    for (int i = 0; i < n; i++) {
      int t = a[i];

      int p1 = l1.get(t);
      int p2 = l2.get(t);

      if (p2 < p1) {
        int c = p1;
        p1 = p2;
        p2 = c;
      }

      if (p2 < n) {
        swap(p2, i);
        actions.add((p2 + 1) + " " + (i + 1));
      } else {
        p2 -= n;
        swap(p2, p2);
        actions.add((p2 + 1) + " " + (p2 + 1));
        swap(p2, i);
        actions.add((p2 + 1) + " " + (i + 1));
      }
    }

    out.println(actions.size());
    for (String action : actions) {
      out.println(action);
    }
  }
}