#include <bits/stdc++.h>
using namespace std;
int n;
vector<int> a;
vector<int> b;
void solve_bf() {
}
void solve_bequal() {
int x = b[1];
int last = 0;
bool ok = false;
int ans = 0;
a.push_back(x + 1);
for(int i = 1; i <= (n + 1); ++i) {
if(a[i] > x) {
if(ok) {
ans += i - last - 1;
ok = false;
}
last = i;
} else if(a[i] == x) {
ok = true;
}
}
cout << ans << "\n";
}
void solve_astrictlyincreasing() {
vector<int> dp(1 + n, 0);
for(int i = 1; i <= n; ++i) {
vector<int> cnt_left(1 + i + 1, 0);
// vector<int> cnt_right(1 + i + 1, 0);
for(int j = 1; j <= i; ++j) {
cnt_left[j] = cnt_left[j - 1];
if(b[j] == a[i]) ++cnt_left[j];
}
/*for(int j = i; j >= 1; --j) {
cnt_right[j] = cnt_right[j + 1];
if(b[j] == a[i]) ++cnt_right[j];
}*/
int maxi = 0;
for(int j = 1; j <= i; ++j) {
maxi = max(maxi, dp[j] - cnt_left[j]);
dp[j] = max(dp[j], maxi + cnt_left[j]);
}
}
cout << dp[n] << "\n";
}
void solve() {
cin >> n;
a.assign(1 + n, 0);
b.assign(1 + n, 0);
for(int i = 1; i <= n; ++i) cin >> a[i];
for(int i = 1; i <= n; ++i) cin >> b[i];
set<int> b_set;
for(int i = 1; i <= n; ++i) {
b_set.insert(b[i]);
}
/*if(n <= 10) {
solve_bf();
} else */if(b_set.size() == 1) {
solve_bequal();
} else {
solve_astrictlyincreasing();
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}
