#include <algorithm>
#include <iostream>
#include <vector>
#include <string>
#include <set>
using namespace std;
typedef unsigned int uint;
int main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n;
cin >> n;
vector<int> a(n), upto(n); // sorted upto
for (int i = 0; i < n; ++i)
cin >> a[i];
upto[n - 1] = n - 1;
for (int i = n - 2; i >= 0; --i)
upto[i] = (a[i] <= a[i + 1] ? upto[i + 1] : i);
set<int> x;
vector<int> dp(n, n);
for (int i = 0; i < n; ++i)
{
auto it = x.upper_bound(a[i]);
int r;
if (it == x.end())
r = upto[i];
else
r = prev(upper_bound(a.begin() + i, a.begin() + upto[i] + 1, *it)) - a.begin();
dp[r] = min(dp[r], (i ? dp[i - 1] : 0) + 1);
x.insert(a[i]);
}
cout << dp[n - 1];
}
