//In the name of God
#include<bits/stdc++.h>
using namespace std;
typedef long long int lli;
typedef long double ld;
typedef pair<lli,lli> pii;
typedef pair<pii,pii> piiii;
typedef vector<lli> ve;
typedef vector<pii> vp;
const lli N=1e6+100;
const lli mod=1e9+7;//998244353;//1e9+9
const lli INF=1e18;
lli power(lli x,lli y){lli res = 1;x = x % mod;while(y>0){if( y & 1 ){res = (res * x) % mod;}y = y >> 1;x = (x * x)%mod;}return res;}
lli modinv(lli x){return power(x,mod-2);}
lli divide(lli x,lli y){return ((x%mod) * modinv(y))%mod;}
#define all(v) v.begin(),v.end()
#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))
#define migmig ios_base::sync_with_stdio(false),cout.tie(0), cin.tie(0);
#define read freopen("input.txt", "r", stdin);freopen("output.txt", "w", stdout);
#define minheap priority_queue<pair<lli,pii>, std::vector<pair<lli,pii>>, std::greater<pair<lli,pii>>>
#define set_preci(x) cout << fixed << setprecision(x);
#define debug(x) cerr << (#x) << " " << (x) << endl
#define MP make_pair
#define PB push_back
#define fi first
#define se second
#define SUM(v) accumulate(v.begin(),v.end(), 0LL)
#define FOR(x,n) for(lli x = 0; x < n; x++)
#define FORS(x,n) for(lli x = 1; x <= n; x++)
#define TEST int TQPWIEJR; cin>>TQPWIEJR;while(TQPWIEJR--)
#define BN(l,a) while(l){a.PB(l%2);l/=2;}
#define lb lower_bound
#define ub upper_bound
#define endl "\n"
#define sep " "
#define SZ(X) (lli)X.size()
lli tmp;
lli n,A[N];
lli dp[N];
int main(){
migmig;
cin>>n;
FORS(i,n){
cin>>A[i];
}
FORS(i,n){
dp[i] = INF;
for(lli j = i; j > 0; j --){
bool ok = 1;
for(lli k = j+1; k <= i; k ++){
if(A[k] < A[k-1])ok = 0;
}
for(lli k = 1; k < j; k ++){
if(A[k] > A[j] && A[k] < A[i]){
ok = 0;
}
}
if(ok){
dp[i] = min(dp[i],dp[j-1]+1);
}
}
}
cout<<dp[n]<<endl;
}
