#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
const ll base = 37;//进制
const ll mod = 998244353;//质数
const int inf = 1e9+5;
const int maxn = 5e6+5;
const ll linf = 1e18+5ll;
int main()
{
    cin.tie(NULL);
    cout.tie(NULL);
    ios::sync_with_stdio(false);
    int n;
    cin>>n;
    vector<string>v(n);
    for(int i = 0;i<n;i++)
    {
        cin>>v[i];
    }
    ranges::sort(v,[](string a,string b){
        return a.size()<b.size();
    });
    set<string>st;
    int ans = 0;
    for(int i = 0;i<n;i++)
    {
        int len = v[i].size();
        if(len==1)
        {
            st.insert(v[i]);
            ans = max(ans,len);
        }
        else
        {
            
            if(st.count(v[i].substr(0,len-1))&&st.count(v[i].substr(1,len-1)))
            {
                st.insert(v[i]);
                ans = max(ans,len);
            }
        }
    }
    cout<<ans<<endl;
    return 0;
}