#include<bits/stdc++.h> using namespace std; int n; int a[24]; int sum[1<<24],f[1<<24]; int main(){ freopen("cloud.in","r",stdin); freopen("cloud.out","w",stdout); cin>>n;; for(int i=1;i<=n;i++) cin>>a[i]; for(int i=1;i<n;i++) a[i]=a[i+1]-a[i]; int maxn=(1<<n)-1; for(int i=1;i<=maxn;i++){ int g= __builtin_ctz(i); sum[i]=sum[i^(1<<g)]+a[g+1]; int t=i; while(t!=0){ int g= __builtin_ctz(t); f[i]=max(f[i],f[i^(1<<g)]); t^=1<<g; } if(!sum[i]) f[i]++; } cout<<n-f[maxn]; }