#include <bits/stdc++.h>
#define fi first
#define se second
#define ld long double
#define pii std::pair<int, int>
#define piii std::pair<pii, pii>
#define rep(i,a) for (int i = 0; i < a; ++i)
#define per(i,a) for (int i = a - 1; i >= 0; --i)
const int maxn = 1e6 + 5;
const int INF = 1e9;
int N;
int a[maxn + 5];
int dp[maxn + 5];
struct segment_tree {
int info[4 * maxn + 5];
void modify(int id, int l, int r, int pos, int x) {
if (l == r) {
info[id] = x;
return;
}
int mid = (l + r) >> 1;
if (pos <= mid)
modify(id << 1, l, mid, pos, x);
else
modify(id << 1 | 1, mid + 1, r, pos, x);
info[id] = std::min(info[id << 1], info[id << 1 | 1]);
}
int query(int id, int l, int r, int lb, int rb) {
if (lb <= l && r <= rb) {
return info[id];
}
int mid = (l + r) >> 1;
int a = INF, b = INF;
if (lb <= mid)
a = query(id << 1, l, mid, lb, rb);
if (rb > mid)
b = query(id << 1 | 1, mid + 1, r, lb, rb);
return std::min(a, b);
}
void modify(int pos, int x) {
modify(1, 1, N, pos, x);
}
int query(int l, int r) {
return query(1, 1, N, l, r);
}
} ST;
void solve() {
std::cin >> N;
for (int i = 1; i <= N; ++i)
std::cin >> a[i];
for (int i = 1; i <= 4 * N; ++i) ST.info[i] = INF;
ST.modify(1, 0);
int pos = 1;
std::set<int> s;
std::vector<int> vec;
for (int i = 1; i <= N; ++i) {
if (a[i] < a[i - 1]) {
for (int j = pos; j < i; ++j)
s.insert(a[j]);
pos = i;
vec.clear();
}
vec.push_back(a[i]);
// [pos...i]
int val = 0;
auto ptr = s.lower_bound(a[i]);
if (ptr != s.begin()) {
ptr--;
val = *ptr;
}
int vt = lower_bound(vec.begin(), vec.end(), val) - vec.begin();
dp[i] = ST.query(pos + vt, i) + 1;
if (dp[i] != INF)
ST.modify(i + 1, dp[i]);
}
std::cout << dp[N] << '\n';
}
int main() {
// std::freopen("input.txt", "r", stdin);
// std::freopen("palin.inp", "r", stdin);
// std::freopen("sushi.out", "w", stdout);
std::ios_base::sync_with_stdio(false);
std::cin.tie(0);
int T = 1;
// std::cin >> T;
while (T--)
solve();
}
// 14 / 2 (87.5% Rate)
