#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MASK(x) (1LL << (x))
#define BIT(x, i) (((x) >> (i)) & 1)
#define SZ(x) ((int) (x).size())
#define ALL(a) (a).begin(), (a).end()
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define debug(x) cout << "[" << #x << " = " << (x) << "]" << endl
#define left __left
#define right __right
#define prev __prev
#define next __next
#define fi first
#define se second
template <class X, class Y>
bool maximize(X &x, Y y) {
if (x < y) return x = y, true;
else return false;
}
template <class X, class Y>
bool minimize(X &x, Y y) {
if (x > y) return x = y, true;
else return false;
}
#define MAX_N 100'100
int a[MAX_N + 2], b[MAX_N + 2], lef[MAX_N + 2], rig[MAX_N + 2];
int n;
void prepare() {
stack <int> st;
FOR(i, 1, n) lef[i] = 0, rig[i] = n + 1;
FOR(i, 1, n) {
while (!st.empty() && a[st.top()] < a[i]) st.pop();
if (!st.empty()) lef[i] = st.top() + 1;
st.push(i);
}
while (!st.empty()) st.pop();
FORD(i, n, 1) {
while (!st.empty() && a[st.top()] < a[i]) st.pop();
if (!st.empty()) rig[i] = st.top() - 1;
st.push(i);
}
}
namespace subtask1356 {
bool check() {
return (n <= 5000);
}
int dp[5050][5050];
void solve() {
memset(dp, 0, sizeof(dp));
int ans = 0;
FOR(j, 1, n) FOR(i, 1, n) {
dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
if (a[i] == b[j] && lef[i] <= j && j <= rig[i]) {
dp[i][j] = dp[i][j - 1] + 1;
}
maximize(ans, dp[i][j]);
}
cout << ans;
}
};
namespace subtask2 {
bool check() {
FOR(i, 2, n) if (b[i] != b[1]) return false;
return true;
}
void solve() {
int ans = 0;
bool have = false;
int cnt = 0;
FOR(i, 1, n) {
if (a[i] <= b[i]) {
++cnt;
have |= (a[i] == b[i]);
} else {
ans += have * cnt;
have = false;
cnt = 0;
}
}
ans += have * cnt;
cout << ans;
}
};
struct BIT {
int bit[MAX_N + 2];
void update(int x, int v) {
for (; x <= n; x += x & (-x)) maximize(bit[x], v);
}
int get(int x) {
int ans = 0;
for (; x > 0; x -= x & (-x)) maximize(ans, bit[x]);
return ans;
}
} fen;
namespace subtask4 {
int dp[MAX_N + 2];
int pos[2 * MAX_N + 2];
void solve() {
memset(pos, 0, sizeof(pos));
FOR(i, 1, n) pos[a[i]] = i;
FOR(j, 1, n) {
int i = pos[b[j]];
if (i == 0) continue;
if (lef[i] <= j && j <= rig[i]) {
dp[j] = fen.get(i) + 1;
fen.update(i, dp[j]);
}
}
cout << *max_element(dp + 1, dp + 1 + n);
}
};
void compressed() {
vector <int> v;
FOR(i, 1, n) v.push_back(a[i]);
FOR(i, 1, n) v.push_back(b[i]);
sort(ALL(v));
v.resize(unique(ALL(v)) - v.begin());
FOR(i, 1, n) a[i] = lower_bound(ALL(v), a[i]) - v.begin() + 1;
FOR(i, 1, n) b[i] = lower_bound(ALL(v), b[i]) - v.begin() + 1;
}
int main() {
ios_base::sync_with_stdio(false);cin.tie(nullptr);
#define task "test"
if (fopen(task".inp","r")) {
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
cin >> n;
FOR(i, 1, n) cin >> a[i];
FOR(i, 1, n) cin >> b[i];
compressed();
prepare();
if (subtask1356 :: check()) return subtask1356 :: solve(), 0;
if (subtask2 :: check()) return subtask2 :: solve(), 0;
subtask4 :: solve();
return 0;
}
/* Discipline - Calm */
