#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
#define ll long long
#define ld long double
#define pii pair<int,int>
#define all(x) (x).begin(), (x).end()
#define isz(x) (int)(x.size())
#define vi vector<int>
template<typename T>
using ost = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const int sz = 1e6+10, inf = 1e9;
const ll mod = 1e9+7, INF = 1e18;
int a[sz];
int st[sz<<2];
void update(int l, int r, int v, int pos, int val){
if (l > pos || pos > r) return;
if (l == r) {
st[v] = (st[v] > val ? val : st[v]);
return;
}
int mid = (l+r)>>1;
update(l, mid, v<<1, pos, val);
update(mid+1, r, v<<1|1, pos, val);
st[v] = min(st[v<<1], st[v<<1|1]);
}
int getans(int l, int r, int ql, int qr, int v) {
if (r < ql || l > qr) return inf;
if (ql <= l && r <= qr) return st[v];
int mid = (l+r)>>1;
return min(getans(l, mid, ql, qr, v<<1), getans(mid+1, r, ql, qr, v<<1|1));
}
void solve(int tc) {
int n; cin >> n;
for (int i = 1; i <= n; i++)
cin >> a[i];
fill(st, st+(sz<<2), inf);
int ans = 0, idx = 1;
int l = 1, r = 1;
auto check = [&](int i, int j){
if (a[i] == a[j] || a[j] - a[i] == 1) return true;
int res = getans(1, sz, a[i]+1, a[j]-1, 1);
return (res == idx || res == inf);
};
while (r <= n) {
int prev = 0;
while (prev <= a[r] && r <= n && check(l, r)) {
prev = a[r];
update(1, sz, 1, a[r], idx);
r++;
}
assert(a[l] <= a[r - 1]);
l = r;
ans++;
idx++;
}
cout << ans << '\n';
}
void precompute() {}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
#ifdef LOCAL
freopen("err.log", "w", stderr);
#endif
precompute();
int t = 1;
// cin >> t;
for (int tc = 1; tc <= t; tc++) solve(tc);
return 0;
}
