#include <bits/stdc++.h>
// #pragma GCC optimize("O3")
#define int long long
#define ll long long
#define pb push_back
#define fi first
#define se second
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define ld long double
using namespace std;
typedef pair<int,int> pii;
typedef pair<pii,pii> ipii;
const int MAXN = 5e3+10;
const int MAXA = 2e5;
const int INF = 1e9+100;
const int SQRT = 500;
const int LOG = 24;
const int MOD = 1e9+7;
void chmn(auto &a, auto b){ a = min(a, b); }
void chmx(int &a, int b){ a = max(a, b); }
int sum(int a, int b){ a %= MOD; b %= MOD; return (a+b)%MOD; }
int sub(int a, int b){ a %= MOD; b %= MOD; return (a+MOD-b)%MOD; }
void chsum(int &a, int b){ a %= MOD; b %= MOD; a = (a+b)%MOD; }
void chsub(int &a, int b){ a %= MOD; b %= MOD; a = (a+MOD-b)%MOD; }
int mul(int a, int b){ a %= MOD; b %= MOD; return a*b%MOD;}
void chmul(int &a, int b){ a = a*b%MOD; }
int expo(int a, int b){
if(b==0) return 1;
int te = expo(a, b/2); te = mul(te, te);
return (b%2 ? mul(te, a) : te);
}
int n, a[MAXN], dp[MAXN], cost[MAXN][MAXN];
struct seg {
int st[2*MAXN];
int que(int x){
int te = 0;
for(; x>=1; x-=(x&(-x))) te += st[x];
return te;
}
void upd(int x, int p){
for(; x<=2*MAXN-20; x+=(x&(-x))) st[x] += p;
}
} A;
signed main(){
// ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>n;
for(int i=1; i<=n;i++) cin>>a[i];
for(int i=1; i<=n; i++){
for(int j=i; j<=n; j++){
// cost[i][j], yg >=i, pindahin j...i
unordered_map <int,int> ma;
for(int p=1; p<=n; p++){
if(a[p]>=i){
A.upd(p, 1); ma[a[p]] = p;
}
}
for(int k=j; k>=i; k--){
int id = ma[k];
cost[i][j] += A.que(id)-1;
A.upd(id,-1);
}
for(int k=j+1; k<=n; k++)
A.upd(ma[k], -1);
}
}
for(int i=1; i<=n; i++){
dp[i] = INF;
for(int j=0; j<=i-1; j++)
chmn(dp[i], dp[j]+cost[j+1][i]);
}
cout << dp[n] << '\n';
}
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