#include <iostream>
#include <iomanip>
#include <vector>
#include <cmath>
#include <algorithm>
#include <set>
#include <queue>
#include <map>
#include <unordered_map>
#include <stack>
#include <bitset>
#include <string>
#include <cstring>
#include <iterator>
#include <random>
#define ll long long
#define ld long double
#define inf (ll)(2*1e18)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define pb push_back
//#define endl "\n"
using namespace std;
void solve(){
ll n, i, j, last;
cin>>n;
vector<ll> a(n+1);
vector<ll> b(n+1);
vector<ll> dp(n+1);
vector<ll> d(n+1);
for(i=0;i<n;++i){
cin>>a[i];
b[a[i]] = i;
}
for(i=2;i<=n;++i){
last = 0;
for(j=b[i]+1;j<n;++j){
if(a[j] < i) d[i-1]++, last++;
}
dp[i] = dp[i-1] + last;
for(j=i-2;j>=0;--j){
if(b[j+1] > b[i]){
--last;
}else{
++last;
}
d[j] += last;
dp[i] = min(dp[i], dp[j] + d[j]);
}
}
cout<<dp[n]<<endl;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
srand(time(nullptr));
ll t=1;
// cin>>t;
for(;t>0;--t){
solve();
}
return 0;
}
