//Was yea ra,rra yea ra synk sphilar yor en me exec hymme METAFALICA waath!
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2")
#include<bits/stdc++.h>
using namespace std;
#define rg register
#define ll long long
#define ull unsigned ll
#define lowbit(x) (x&(-x))
#define djq 998244353
const short sint=0x3f3f;
const int inf=0x3f3f3f3f;
const ll linf=0x3f3f3f3f3f3f3f3f;
const double alpha=0.73;
const double PI=acos(-1);
inline void file(){
	freopen("ball.in","r",stdin);
	freopen("ball.out","w",stdout);
}
char buf[1<<21],*p1=buf,*p2=buf;
inline int getc(){
    return p1==p2&&(p2=(p1=buf)+fread(buf,1,(1<<20)+5,stdin),p1==p2)?EOF:*p1++;
}
//#define getc getchar
inline ll read(){
	rg ll ret=0,f=0;char ch=getc();
    while(!isdigit(ch)){if(ch==EOF)exit(0);if(ch=='-')f=1;ch=getc();}
    while(isdigit(ch)){ret=ret*10+ch-48;ch=getc();}
    return f?-ret:ret;
}
inline int rdstr(char* s){
	char ch=getc(); int len(0);
	while(ch<33||ch>126) ch=getc();
	while(ch>=33&&ch<=126) (*s++)=ch,++len,ch=getc();
	return len;
}
#define ep emplace
#define epb emplace_back
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define it iterator
#define mkp make_pair
#define naive return 0*puts("Yes")
#define angry return 0*puts("No")
#define fls fflush(stdout)
#define rep(i,a) for(rg int i=1;i<=a;++i)
#define per(i,a) for(rg int i=a;i;--i)
#define rep0(i,a) for(rg int i=0;i<=a;++i)
#define per0(i,a) for(rg int i=a;~i;--i)
#define szf sizeof
typedef vector<int> vec;
typedef pair<int,int> pii;
struct point{ int x,y; point(int x=0,int y=0):x(x),y(y) {} inline bool operator<(const point& T)const{ return x^T.x?x<T.x:y<T.y; }; };
inline int ksm(int base,int p){int ret=1;while(p){if(p&1)ret=1ll*ret*base%djq;base=1ll*base*base%djq,p>>=1;}return ret;}
inline void pls(int& x,const int k){ x=(x+k>=djq?x+k-djq:x+k); }
inline int add(const int a,const int b){ return a+b>=djq?a+b-djq:a+b; }
inline void sub(int& x,const int k){ x=(x-k<0?x-k+djq:x-k); }
inline int inc(const int a,const int b){ return a<b?a-b+djq:a-b; }
inline void ckmn(int& x,const int k){ x=(k<x?k:x); }
inline void ckmx(int& x,const int k){ x=(k>x?k:x); }
inline void ckmn(ll& x,const ll k){ x=(k<x?k:x); }
inline void ckmx(ll& x,const ll k){ x=(k>x?k:x); }
//mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());


int n,f[1<<24];
ll ans,a[25],b[25];
signed main(){
	//file();
	n=read();
	rep(i,n) a[i]=read(),b[i]=a[i]-a[i-1];
	b[n+1]=-a[n]; ++n;
	f[0]=0;
	for(rg int i=1;i<(1<<n);++i){
		ll sum(0);
		for(rg int j=0;j<n;++j) 
			if((i>>j)&1) sum+=b[j+1],ckmx(f[i],f[i^(1<<j)]);
		if(!sum) ++f[i];
	}
	printf("%d\n",n-f[(1<<n)-1]);
	return 0;
}
/*

*/