#include <bits/stdc++.h>

#define rep(i,s,n) for(int i = int(s); i < int(n); i++)
#define rrep(i,s,n) for(int i = int(n) - 1; i >= int(s); i--)
#define all(v) (v).begin(), (v).end()

using ll = long long;
using ull = unsigned long long;
using ld = long double;

template<class T>
bool chmin(T &a, T b) {
    if(a <= b) return false;
    a = b;
    return true;
}

template<class T>
bool chmax(T &a, T b) {
    if(a >= b) return false;
    a = b;
    return true;
}

using namespace std;

int main() {
    int n; cin >> n;
    vector<ll> a(n+2,0);
    rep(i,1,n+1) cin >> a[i];
    vector<ll> b(n+1);
    rep(i,0,n+1) b[i] = a[i+1] - a[i];
    n++;
    vector<ll> sum(1<<n,0);
    rep(s,0,1<<n){
        rep(i,0,n){
            if (s >> i & 1){
                sum[s] += b[i];
            }
        }
    }
    vector<int> dp(1<<n,0);
    rep(s,1,1<<n){
        rep(i,0,n){
            if (s >> i & 1){
                chmax(dp[s],dp[s^(1<<i)]);
            }
        }
        if (sum[s] == 0) dp[s]++;
    }
    cout << n-dp[(1<<n)-1] << endl;
}