#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
#define int long long
#define fi first
#define se second
#define pb push_back
#define debug(x) cout<<#x<<": "<<x<<"\n"
signed main()
{
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
// freopen("input.000","r",stdin);
// freopen("output.000","w",stdout);
// srand((unsigned)time(NULL));
// rand()
int n,i,j,k,a[5005],dp[5005],b[5005],m,cost,pos[5005];
ordered_set s;
cin>>n;
for (i=1;i<n+1;i++) cin>>a[i];
dp[n]=dp[n+1]=0;
for (i=n-1;i>0;i--)
{
dp[i]=1e12;
m=0;
for (j=1;j<n+1;j++) if (a[j]>=i)
{
m++;b[m]=a[j];
}
for (j=1;j<m+1;j++) pos[b[j]]=j;
for (j=i+1;j<=n+1;j++)
{
while (s.begin()!=s.end()) s.erase(s.begin());
for (k=j;k<n+1;k++) s.insert(pos[k]);
cost=0;
for (k=i;k<j;k++)
{
cost += s.order_of_key(pos[k]);
s.insert(pos[k]);
}
// cout<<i<<" "<<j<<" "<<cost<<"\n";
dp[i]=min(dp[i], cost + dp[j]);
}
}
cout<<dp[1];
}
