#include <bits/stdc++.h>

#include <atcoder/all>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define FAST_IO                \
  ios::sync_with_stdio(false); \
  cin.tie(0);
const i64 INF = 1001001001001001001;
using Modint = atcoder::static_modint<998244353>;

int main() {
  FAST_IO

  int T;
  cin >> T;
  while (T--) {
    string N;
    cin >> N;

    int n = N.size();
    vector<int> a(n);
    iota(a.begin(), a.end(), 0);

    bool found = false;
    int mn = 1e9 + 10;
    do {
      int x = 0;
      for (int i = 0; i < n; ++i) {
        x = x * 10 + (N[a[i]] - '0');
      }
      int sqX = sqrt(x);
      if (sqX * sqX == x) {
        mn = min(mn, sqX);
        found = true;
      }
    } while (next_permutation(a.begin(), a.end()));
    if (!found) {
      cout << -1 << endl;
    } else {
      cout << mn * mn << endl;
    }
  }
}