#include<bits/stdc++.h>
using namespace std;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define lli long long int
#define vi vector<int>
#define vlli vector<long long int>
#define pii pair<int, int>
#define plli pair<lli, lli>
#define rep(i, a, b) for(lli i = (a); i <= (b); i++)
#define repa(i, a, b) for(lli i = (a); i >= (b); i--)
#define repv(x, v) for(auto x : v)
#define debug(x) cout << #x << " = " << x << endl
#define debugsl(x) cout << #x << " = " << x << ", "
#define debugarr(x, a, b) cout << #x << " = ["; rep(ii, a, b) cout << x[ii] << ", "; cout << "]\n"
#define pb push_back
#define nl "\n"
#define MAX_N 5002
#define INF (1ll << 62)
lli n, h[MAX_N], dp[MAX_N];
lli costo(lli l, lli r){
vlli tmp;
lli pos, cnt, offset;
rep(i, 1, n) if (h[i] >= l) tmp.pb(h[i]);
cnt = offset = 0;
repa(i, r, l){
rep(j, 0, tmp.size() - 1) if (tmp[j] == i){ pos = j; break; }
repa(j, pos, offset + 1){
swap(tmp[j], tmp[j - 1]);
++cnt;
}
++offset;
}
return cnt;
}
int main()
{
fastio;
cin >> n;
rep(i, 1, n) cin >> h[i];
rep(i, 1, n){
dp[i] = INF;
rep(j, 0, i - 1){
dp[i] = min(dp[i], dp[j] + costo(j + 1, i));
}
}
cout << dp[n];
return 0;
}
