#include<bits/stdc++.h>

#ifndef ONLINE_JUDGE
#include "debug.h"
#else
#define debug(...) 42
#endif

using i64 = long long;
#define int long long

namespace ranges = std::ranges;

void solve()
{
#define tests
    std::string s; std::cin >> s; int n{std::ssize(s)};

    auto check = [&](int len) {
        for (int i = 0; i + len - 1 < n; i++) {
            for (int j = i + len; j + len - 1 < n; j++) {
                if (s.substr(i, len) == s.substr(j, len)) {return true;}
            }
        }
        return false;
    };

    int lo{}, hi{n}; while (lo <= hi) {int mid{hi + lo >> 1}; check(mid) ? lo = mid + 1 : hi = mid - 1;}
    int len{lo - 1};
    for (int i = 0; i + len - 1 < n; i++) {
        for (int j = i + len; j + len - 1 < n; j++) {
            if (s.substr(i, len) == s.substr(j, len)) {std::cout << s.substr(i, len) << "\n"; return ;}
        }
    }

}

signed main()
{
   std::cin.tie(nullptr)->sync_with_stdio(false);
   int _(1);
#ifdef tests
   std::cin >> _;
#endif
   while(_--) solve();
   return 0;
}