#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  using arr = array<int, 10>;
  map<arr, int> mp;
  for (int i = 1; i * i <= 1'000'000'000; ++i) {
    int x = i * i;
    string s = to_string(x);
    arr a = { 0 };
    for (char c : s) a[c - '0']++;
    if (!mp.contains(a)) mp[a] = x;
  }
  int q;
  cin >> q;
  while (q--) {
    string s;
    cin >> s;
    arr a = { 0 };
    for (char c : s) a[c - '0']++;
    constexpr int INF = 1e9;
    int ans = INF;
    do {
      if (mp.contains(a)) ans = min(ans, mp[a]);
      a[0]--;
    } while (a[0] >= 0);
    if (ans != INF) {
      cout << ans << '\n';
    }
    else {
      cout << -1 << '\n';
    }
  }
  return 0;
}