#include<bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
#define ykh mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define __lg(x) 63-__builtin_clzll(x)
#define pow2(x) (1LL<<x)
void __print(int x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef local
void setio(){freopen("/Users/iantsai/Library/Mobile Documents/com~apple~CloudDocs/cpp/Empty.md","r",stdin);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
void setIO(string s) {
freopen((s + ".in").c_str(), "r", stdin);
freopen((s + ".out").c_str(), "w", stdout);
}
struct line{
int a,b;
int operator()(const int x)const{
return a*x+b;
}
};
bool check(line l1,line l2,line l3){
return (l3.b-l2.b)*(l1.a-l2.a)<=(l2.b-l1.b)*(l2.a-l3.a);
}
const int mxn=5005;
int bit[2][mxn];
void modify(int p,int v,bool f){
for(;p<mxn;p+=p&-p){
bit[f][p]+=v;
}
}
int query(int p,bool f){
int res=0;
for(;p;p-=p&-p){
res+=bit[f][p];
}
return res;
}
signed main(){
setio();
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int n;
cin>>n;
vector<int>v(n+1),pos(n+1);
for(int i=1;i<=n;i++){
cin>>v[i];
pos[v[i]]=i;
}
vector<int>dp(n+1,1e18);
dp[0]=0;
for(int i=1;i<=n;i++){
for(int j=n;j>i;j--){
modify(pos[j],1,0);
}
int sum=0;
for(int j=i;j>=1;j--){
sum+=query(pos[j],0);
sum+=query(n,1)-query(pos[j],1);
dp[i]=min(dp[i],dp[j-1]+sum);
modify(pos[j],1,1);
debug(sum);
}
for(int j=n;j>i;j--){
modify(pos[j],-1,0);
}
for(int j=i;j>=1;j--){
modify(pos[j],-1,1);
}
debug(dp);
}
cout<<dp[n]<<'\n';
}
/*
input:
*/
