#include<bits/stdc++.h>
#define debug(x) cerr<<#x<<":"<<x<<'\n';
using namespace std;
using ll = long long;
using ull = unsigned long long;
const int N = 1e5 + 5, MOD = 1e9 + 7;
int n;
string s[N];
template<int P, int M> 
struct Hashing 
{
    int n;
    std::vector<int> h, p;
    Hashing() {}
    Hashing(const std::string& s) {
        build(s);
    }
    void build(const std::string& s) {
        n = s.size();
        h.resize(n + 1);
        p.resize(n + 1);
        p[0] = 1;
        for (int i = 1; i <= n; i++) h[i] = ( 1ll * h[i - 1] * P + s[i - 1]) % M;
        for (int i = 1; i <= n; i++) p[i] = 1ll * p[i - 1] * P % M;
    }
    int get(int l, int r) {
        int res = (h[r] - (1ll * h[l - 1] * p[r - l + 1]) % M) % M;
        return res < 0 ? res + M : res;
    }
};
using strhash = Hashing <13331, MOD>;
bool cmp(string &x,string &y)
{
    return x.size() < y.size();
}
void solve()
{
    cin>>n;
    vector <set<int>> st(N);
    for(int i=1;i<=n;i++)
    {
        cin>>s[i];
        auto ths = strhash(s[i]);
        // debug(ths.get(1, s[i].size()))
        st[s[i].size()].insert(ths.get(1, s[i].size()));
    } 
    sort(s+1,s+n+1,cmp);
    int idx = 1;
    for(int i=1;i<=n;i++) if(s[i].size()==idx) idx ++;
    idx --;
    int ans = 0;
    for(int i=1;i<=n;i++)
    {
        if(s[i].size()>idx) break;
        bool flag = 1;
        auto ths = strhash(s[i]);
        for(int j=0;j<s[i].size() && flag;j++)
        {
            for(int k=j;k<s[i].size() && flag;k++) // [j,k]
            {
                int len = k - j + 1;
                if(!st[len].count(ths.get(j+1,k+1)))
                {
                    flag = 0;
                    break;
                }
            }
        }
        if(flag) ans = max(ans,(int)s[i].size());
    }
    cout<<ans;
}
int main(void)
{
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    int T = 1;
    // cin >> T;
    while(T--) solve();
    return 0;
}