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#include <iostream>
    #include <stdio.h>
    using namespace std;
   

  const int MOD = 1000000007;
  const int N = 500000;
  int EMPTY = -1;
  int n;
  int tree[2][N + 1][4];
  int PARENT = 0;
  int LEFT = 1;
  int RIGHT = 2;
  int SIZE = 3;

  int abs(int x) {
    return x >= 0 ? x : -x;
  }

  int linearize(int iTree, int leftBound, int rightBound) {
    int count = 0;
    for (int i = leftBound; i <= rightBound; i++) {
      int parent = tree[iTree][i][PARENT];
      if (parent != EMPTY) {
        int grandparent = tree[iTree][parent][PARENT];
        if (grandparent != EMPTY &&
            leftBound <= grandparent &&
            grandparent <= rightBound) {
          // if parent and grandparent are on opposite sides
          if (parent < i && i < grandparent
              || grandparent < i && i < parent) {
            // we need to rotate this node plus all children (=SIZE)
            count += tree[iTree][i][SIZE];
            count %= MOD;
          }
        }
      }
    }
    return count;
  }

  int compare(int rootA, int rootB) {
    // find common left
    int leftA = rootA;
    int leftB = rootB;
    while (leftA != leftB) {
      if (leftA < leftB) {
        leftB = tree[1][leftB][LEFT];
      } else if (leftB < leftA) {
        leftA = tree[0][leftA][LEFT];
      }
    }

    // find common right
    int rightA = rootA;
    int rightB = rootB;
    while (rightA != rightB) {
      if (rightA < rightB) {
        rightA = tree[0][rightA][RIGHT];
      } else if (rightB < rightA) {
        rightB = tree[1][rightB][RIGHT];
      }
    }

    // found commmon left and right
    int left = leftA;
    int right = rightA;

    // include rotating to common root
    int result = abs(rootA - rootB);

    // include cost of making range linear
    for (int iTree = 0; iTree < 2; iTree++) {
      result += linearize(iTree, left, right);
      result %= MOD;
    }

    // include recursion to left side
    if (tree[0][left][LEFT] != EMPTY) {
      result += compare(
          tree[0][left][LEFT],
          tree[1][left][LEFT]);
      result %= MOD;
    }
    // include recursion to right side
    if (tree[0][right][RIGHT] != EMPTY) {
      result += compare(
          tree[0][right][RIGHT],
          tree[1][right][RIGHT]);
      result %= MOD;
    }
    return result;
  }

  int main() {
    cin >> n;

    int roots[2];
    for (int iTree = 0; iTree < 2; iTree++) {
      for (int iNode = 1; iNode <= n; iNode++) {
        tree[iTree][iNode][LEFT] = EMPTY;
        tree[iTree][iNode][RIGHT] = EMPTY;
      }
    }

    // initialize PARENT, LEFT, RIGHT
    for (int iTree = 0; iTree < 2; iTree++) {
      for (int iNode = 1; iNode <= n; iNode++) {
        int parent;
        cin >> parent;
        tree[iTree][iNode][PARENT] = parent;
        tree[iTree][iNode][SIZE] = EMPTY;
        if (parent == EMPTY) {
          roots[iTree] = iNode;
        } else {
          if (iNode < parent) {
            tree[iTree][parent][LEFT] = iNode;
          }
          if (parent < iNode) {
            tree[iTree][parent][RIGHT] = iNode;
          }
        }
      }
    }

    // calculate sizes
    for (int iTree = 0; iTree < 2; iTree++) {
      int index = 1;
      while (true) {
        int left = tree[iTree][index][LEFT];
        int right = tree[iTree][index][RIGHT];

        if (left != EMPTY && tree[iTree][left][SIZE] == EMPTY) {
          index = left;
          continue;
        }
        if (right != EMPTY && tree[iTree][right][SIZE] == EMPTY) {
          index = right;
          continue;
        }
        int size = 1;
        if (left != EMPTY) {
          size += tree[iTree][left][SIZE];
        }
        if (right != EMPTY) {
          size += tree[iTree][right][SIZE];
        }
        tree[iTree][index][SIZE] = size;
        int parent = tree[iTree][index][PARENT];
        if (parent == EMPTY) {
          break;
        } else {
          index = parent;
        }
      }
    }

    int result = compare(roots[0], roots[1]);

    printf("%d", result);
    return 0;
  }