#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
using namespace __gnu_pbds;
using namespace std;
#define pb push_back
#define st first
#define nd second
typedef long long ll;
typedef long double ld;
const ll I = 1000LL * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL;
const ll M = 1000LL * 1000LL * 1000LL + 7LL;
const int N = 5 * 1000 + 7;
int tab[N], pos[N];
int dp[N];
void Solve()
{
int n;
cin >> n;
for(int i = 1; i <= n; ++i)
{
cin >> tab[i];
pos[tab[i]] = i;
}
for(int i = 1; i <= n; ++i)
{
int dod = 0; dp[i] = n * n + 100;
for(int j = i + 1; j <= n; ++j)
if(pos[j] < pos[i]) ++dod;
for(int j = i - 1; j >= 0; --j)
{
dp[j] += dod;
dp[i] = min(dp[i], dp[j]);
if(pos[j] > pos[i]) --dod;
else ++dod;
}
}
cout << dp[n] << "\n";
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//int t; cin >> t;
//while(t--)
Solve();
return 0;
}
