#include<bits/stdc++.h>
using namespace std;
int a[20],f[20],cnt,cnta,n,ans=2e9;
struct node{
	int start,x;
}line[150];
bool check(int x,int k)
{
	for(int i=x;i<60;i+=k)
	{
		//cout<<i<<" "<<f[i]<<endl;
		if(!f[i])
			return 0;
	}
	return 1;
}
bool cmp(node x,node y)
{
	return x.x>y.x;
}
void dfs(int x,int temp)
{
	//cout<<x<<" "<<line[x].start<<" "<<line[x].x<<endl;
	if(!n)
	{
		ans=min(ans,temp);
		return ;
	}
	for(int i=x;i<=cnta;i++)
	{
		if(temp+n/line[i].x>=ans)
			return ;
		if(!check(line[i].start,line[i].x))
			continue;
		for(int j=line[i].start;j<60;j+=line[i].x)
		{
			n--;
			f[j]--;
		}
		dfs(i,temp+1);
		for(int j=line[i].start;j<60;j+=line[i].x)
		{
			n++;
			f[j]++;
		}
	}
}
int main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
		f[a[i]]++;
	}
	//cout<<check(2,11)<<endl;
	
	for(int i=1;i<=n;i++)
	{
		cnt=0;
		for(int j=i+1;j<=n;j++)
		{
			if(a[i]==a[j])
				continue;
			//cout<<a[i]<<" "<<a[j]<<" "<<check(a[i],a[j]-a[i])<<endl;
			if(check(a[i],a[j]-a[i]))
				line[++cnta]={a[i],a[j]-a[i]};
		}
	}
	sort(line+1,line+cnta+1,cmp);
	//cout<<endl;
	/*
	for(int i=1;i<=cnta;i++)
	{
		cout<<line[i].start<<" "<<line[i].x<<endl;
	}
	*/
	dfs(1,0);
	cout<<ans<<endl;
	
	return 0;
}