#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define pb push_back
#define db(val) "[" #val " = " << (val) << "] "
const ll mod = 1e9 + 7;
const int maxn = 1e5 + 4;
const int INF = 1e9;
const int N = 5005;
int n, a[maxn], b[maxn], L[maxn], R[maxn], dp[N][N];
set<int> mySet;
void Sub2() {
int res = 0, pre = 0;
for (int i = 1; i <= n; i++)
if (a[i] == b[i]) {
res += R[i] - max(pre, L[i]) - 1;
pre = R[i];
i = R[i] - 1;
}
cout << res;
}
void Sub4() {
}
void Sub6() {
int res = 0;
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++) {
if (a[i] == b[j]) {
if (L[i] < j && j < R[i])
dp[i][j] = dp[i][j - 1] + 1;
}
dp[i][j] = max({dp[i][j], dp[i][j - 1], dp[i - 1][j]});
res = max(res, dp[i][j]);
}
cout << res << '\n';
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
//freopen(".INP", "r", stdin);
//freopen(".OUT", "w", stdout);
cin >> n;
for (int i = 1; i <= n; i++)
cin >> a[i];
for (int i = 1; i <= n; i++) {
cin >> b[i];
mySet.insert(b[i]);
}
stack<int> st;
st.push(0);
a[0] = a[n + 1] = INF + 1;
for (int i = 1; i <= n; i++) {
while (a[st.top()] <= a[i])
st.pop();
L[i] = st.top();
st.push(i);
}
stack<int>().swap(st);
st.push(n + 1);
for (int i = n; i >= 1; i--) {
while (a[st.top()] <= a[i])
st.pop();
R[i] = st.top();
st.push(i);
}
if (mySet.size() == 1) Sub2();
else if (n > 5000) Sub4();
else {
Sub6();
}
}
