#include<map>
#include<cstdio>
#include<string>
#include<algorithm>
#define N 100005
using namespace std;
int n,ans;
string s[N];
map<string,bool> mp;
bool cmp(string x,string y) {return x.length()>y.length();}
int main()
{
	scanf("%d",&n);
	for (int i=1;i<=n;++i)
	{
		char ch=getchar();
		while (ch<'a'||ch>'z') ch=getchar();
		while (ch>='a'&&ch<='z') s[i]+=ch,ch=getchar();
		mp[s[i]]=true;
	}
	sort(s+1,s+n+1,cmp);
	for (int i=1;i<=n;++i)
	{
		int len=s[i].length();
		bool flag=true;
		for (int j=0;flag&&j<len;++j)
			for (int k=1;k+j<=len;++j)
			{
				if (mp.find(s[i].substr(j,k))==mp.end()) {flag=false;break;}
			}
		if (flag)
		{
			printf("%d\n",s[i].size());
			return 0;
		}
	}
	return 0;
}