#include<bits/stdc++.h>
#define int long long
#define For(i, n) for (int i = 0; i < n; i++)
using namespace std;
const int MAXN = 200;
int N, H[MAXN + 5], T[MAXN + 5], dp[MAXN + 5][MAXN + 5];
int f(int L, int R) {
if (L > R) return 0;
if (L == R) {
if (H[L] == T[L]) return 1;
else return 0;
}
// menjadikan semuanya max(H[l], H[l+1], .. , H[r])
int maks = 0;
for (int i = L; i <= R; i++) {
maks = max(maks, H[i]);
}
int cnt = 0;
for (int i = L; i <= R; i++) {
if (T[i] == maks) cnt++;
}
int ans = cnt;
for (int i = L; i <= R - 1; i++) {
ans = max(ans, f(L, i) + f(i + 1, R));
}
return dp[L][R] = ans;
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
memset(dp, -1, sizeof dp);
cin >> N;
For (i, N) cin >> H[i];
For (i, N) cin >> T[i];
cout << f(0, N - 1) << endl;
}
