//雪花飄飄北風嘯嘯
//天地一片蒼茫
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define fi first
#define se second
#define endl '\n'
#define debug(x) cout << #x << " is " << x << endl
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define lb lower_bound
#define up upper_bound
#define rep(x,start,end) for(auto x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()
#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
//change less to less_equal for non distinct pbds, but erase will bug
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
struct FEN{
int fen[5005];
FEN(){
memset(fen,0,sizeof(fen));
}
void update(int i,int k){
while (i<5005){
fen[i]+=k;
i+=i&-i;
}
}
int query(int i){
int res=0;
while (i){
res+=fen[i];
i-=i&-i;
}
return res;
}
int query(int i,int j){
return query(j)-query(i-1);
}
} hi,lo;
int n;
int arr[5005];
int pos[5005];
ll dp[5005];
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin.exceptions(ios::badbit | ios::failbit);
cin>>n;
rep(x,1,n+1) cin>>arr[x];
rep(x,1,n+1) pos[arr[x]]=x;
memset(dp,63,sizeof(dp));
dp[0]=0;
rep(x,0,n){
hi=FEN();
lo=FEN();
rep(y,x+1,n+1) hi.update(pos[y],1);
ll curr=dp[x];
rep(y,x+1,n+1){
curr+=hi.query(1,pos[y]-1);
curr+=lo.query(1,pos[y]-1);
curr-=lo.query(pos[y]+1,5004);
//cout<<x<<" "<<y<<" "<<curr<<endl;
dp[y]=min(dp[y],curr);
hi.update(pos[y],-1);
lo.update(pos[y],1);
}
}
//rep(x,0,n+1) cout<<dp[x]<<" "; cout<<endl;
cout<<dp[n]<<endl;
}
