#include <bits/stdc++.h>
using namespace std;

#define ll long long 
#define lll __int128
#define INF 0x3f3f3f3f
#define LNF 0x3f3f3f3f3f3f3f3fll
#define MOD 998244353
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ld long double
#define fi first
#define se second
#define all(a) a.begin(), a.end()

#define N 5050

int f(ll x) {
    if (!x) return 1;
    if (x%3) return f(x-1)+1;
    return f(x/3)+1;
}

int main() {
#ifdef TEST
    freopen("zz.in", "r+", stdin);
#endif
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n; cin >> n;
    set<string> s;
    vector<string> vs(n);
    for (int i = 0; i < n; ++ i) cin >> vs[i];
    sort(all(vs), [&](auto& a, auto& b) {
        return a.size() < b.size();
    });
    int res = 0;
    s.insert("");
    for (auto& t : vs) {
        s.insert(t);
        int m = t.length() - 1;
        if (s.count(t.substr(0, m)) && s.count(t.substr(1, m))) {
            res = max(res, (int) t.length());
        }
    }
    cout << res << '\n';
}