#include <bits/stdc++.h>
using ll = long long;
using namespace std;
ll dp[2010][2010];
int countnum(int x, int* A, int begin, int end) {
  int cnt = 0;
  for (int i = begin; i < end; i++) {
    if (A[i] == x) cnt++;
  }
  return cnt;
}
int main() {
  int N, M;
  cin >> N >> M;
  int S[N];
  int T[M];
  for (int i = 0; i < N; i++) cin >> S[i];
  for (int i = 0; i < M; i++) cin >> T[i];
  int i = 0;
  int j = 0;
  ll res = 1;
  int ss, tt;
  int MAX = max(N, M);
  while (i < MAX || j < MAX) {
    if (i == j) {
      if (S[i] == T[j]) {
        res += i + 1;
      } else {
        ss = countnum(S[i], S, 0, i);
        tt = countnum(S[i], T, 0, i);
        res += ss + min(ss, tt) + 1;
        ss = countnum(T[i], S, 0, i);
        tt = countnum(T[i], T, 0, i);
        res += +min(ss, tt) + 1;
      }
    } else {
      if (i > j) {
        ss = countnum(S[i], S, 0, i);
        tt = countnum(S[i], T, 0, j);
        res += ss + min(ss, tt) + 1;
      } else {
        ss = countnum(T[j], S, 0, i);
        tt = countnum(T[j], T, 0, j);
        res += +min(ss, tt) + 1;
      }
    }
    if (i < N) i++;
    if (j < M) j++;
  }
  cout << res << endl;
}
