// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
template<class T>
bool minimize(T &a, const T &b) {
if (a > b) return a = b, true;
return false;
}
template<class T>
bool maximize(T &a, const T &b) {
if (a < b) return a = b, true;
return false;
}
#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "gen"
const int MOD = 1e9 + 7;
const int inf = 0x3f3f3f3f;
const ll INF = 1e18 + 27092008;
const int N = 300 + 5;
int n, a[N], f[N];
void init(void) {
cin >> n;
FOR(i, 1, n) cin >> a[i];
}
void process(void) {
memset(f, 0x3f, sizeof f);
f[0] = 0;
FOR(i, 0, n) if (f[i] != inf) {
minimize(f[i + 1], f[i] + 1);
FOR(j, i + 2, n) {
if (a[j-1] > a[j]) break;
bool ok = true;
FOR(x, 1, i) if (a[i+1] < a[x] && a[x] < a[j]) {
ok = false;
break;
}
if (!ok) break;
minimize(f[j], f[i]+1);
}
}
cout << f[n];
FOR(i, 1, n) cerr << f[i] << ' '; cerr << '\n';
cerr << f[n];
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) {
init();
process();
}
return 0;
}
