#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define ff first
#define ss second
#define all(s) s.begin(),s.end()
#define rall(s) s.rbegin(),s.rend()
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int n;
cin>>n;
int p[n+5],f[n+5];
for(int i=1;i<=n;i++){
cin>>p[i];
f[p[i]]=i;
}
int need[n+5][n+5];
memset(need,0,sizeof need);
for(int r=1;r<=n;r++){
int cur=0;
need[r][r]=0;
for(int l=r-1;l>=1;l--){
for(int i=l+1;i<=r;i++){
if(f[i]>f[l]){
cur++;
}
}
need[l][r]=cur;
}
}
int cnt[n+5][n+5];
memset(cnt,0,sizeof cnt);
for(int l=1;l<=n;l++){
int left[n+5],len=0;
int pre[n+5],pos[n+5];
for(int i=1;i<=n;i++){
if(p[i]>=l){
len++;
pos[p[i]]=len;
}
}
pre[0]=0;
for(int i=l;i<=n;i++){
pre[i-l+1]=pre[i-l]+pos[i];
}
int cur=0;
for(int r=l;r<=n;r++){
int x=r-l+1;
cnt[l][r]=need[l][r]+pre[x]-(x*(x+1)/2);
}
}
int dp[n+5];
fill(dp,dp+n+1,1e9);
dp[0]=0;
for(int l=1;l<=n;l++){
for(int r=l;r<=n;r++){
dp[r]=min(dp[r],dp[l-1]+cnt[l][r]);
}
}
cout<<dp[n];
}
