/*
@Date    : 2024-05-23 13:07:58
@Author  : Adscn ([email protected])
@Link    : http://www.cnblogs.com/LLCSBlog
*/
#include<bits/stdc++.h>
#include<bits/extc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
#define IL inline
#define RG register
#define gi geti<int>()
#define gl geti<ll>()
#define gc getchar()
#define File(a) freopen(a".in","r",stdin);freopen(a".out","w",stdout)
template<typename T>IL bool chkmax(T &x,const T &y){return x<y?x=y,1:0;}
template<typename T>IL bool chkmin(T &x,const T &y){return x>y?x=y,1:0;}
template<typename T>
IL T geti()
{
	RG T xi=0;
	RG char ch=gc;
	bool f=0;
	while(!isdigit(ch))ch=='-'?f=1:f,ch=gc;
	while(isdigit(ch))xi=xi*10+ch-48,ch=gc;
	return f?-xi:xi;
}
template<typename T>
IL void pi(T k,char ch=0)
{
	if(k<0)k=-k,putchar('-');
	if(k>=10)pi(k/10);
	putchar(k%10+'0');
	if(ch)putchar(ch);
}
/*
IL unsigned int LOG2(unsigned int x)
{
	unsigned int ret;
	__asm__ __volatile__ ("bsrl %1, %%eax":"=a"(ret):"m"(x));
	return ret;
}
*/
const int Q1=13,Q2=17;
const int P1=1e9+7,P2=1e9+9;
ll pow1[100007],pow2[100007];
unordered_map<ll,int>mp;
//__gnu_pbds::gp_hash_table<ll,int>mp;
string s[100007];
pll thh[100007];
ll calc(int l,int r){
	if(l==0){
		return thh[r].first<<30|thh[r].second;
	}
	--l;
	ll h1=((thh[r].first-thh[l].first*pow1[r-l])%P1+P1)%P1,
		h2=((thh[r].second-thh[l].second*pow2[r-l])%P2+P2)%P2;
	return h1<<30|h2;
}
int main(void)
{
	#ifndef ONLINE_JUDGE
//	File("");
	#endif
	int n=gi;
	pow1[0]=pow2[0]=1;
	for(int i=1;i<=n;++i){
		cin>>s[i];
		pow1[i]=pow1[i-1]*Q1%P1;
		pow2[i]=pow2[i-1]*Q2%P2;
	}
	sort(s+1,s+n+1,[](string &a,string &b){return a.size()<b.size();});
	for(int i=1;i<=n;++i)
	{
		ll hh1=0,hh2=0;
		for(int j=0;j<s[i].size();++j)
			hh1=(hh1*Q1+s[i][j])%P1,hh2=(hh2*Q2+s[i][j])%P2;
		ll hh=hh1<<30|hh2;
		mp[hh]=i;
	}
	for(int i=n;i;--i){
		int m=s[i].size();
		if(m*m>1e5)continue;
		ll hh1=0,hh2=0;
		bool fail=0;
		for(int j=0;j<m;++j)
		{
			hh1=(hh1*Q1+s[i][j])%P1,hh2=(hh2*Q2+s[i][j])%P2;
			thh[j]=make_pair(hh1,hh2);
			for(int k=0;k<=j;++k)
			{
				if(!mp.count(calc(k,j))){
//					printf("(%d,%d) of %d th is not valid\n",k,j,i);
					fail=1;
					break;
				}
			}
			if(fail)break;
		}
		if(fail)continue;
		printf("%d\n",m);
		return 0;
	}
	return 0;
}