#include <iostream>
#include <unordered_map>
#include <string>
#include <algorithm>

int main() {
    std::unordered_map<std::string, int> roots;
    for (int i = 1; i * i <= 1000000000; i++) {
        if (i % 10 == 0) continue;
        int sq = i * i;
        std::string s = std::to_string(sq);
        auto t = s;
        std::sort(t.rbegin(), t.rend());
        roots[t] = sq;
        int max = t.size();
        for (int j = 1; max + j <= 9; j++) {
            t.push_back('0');
            roots[t] = sq;
        }
    }
    int T;
    std::cin >> T;
    while (T--) {
        std::string N;
        std::cin >> N;
        if (N.size() == 10) {
            std::cout << 1 << std::endl;
            continue;
        }
        std::sort(N.rbegin(), N.rend());
        if (roots[N]) std::cout << roots[N] << std::endl;
        else std::cout << -1 << std::endl;
    }
}