import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		Map<String, Integer> map = new HashMap<>();
		for (int i = 1; i * i <= 1000000000; i++) {
			int i2 = i * i;
			int n = i2;
			int[] c = new int[10];
			while (n > 0) {
				c[n % 10]++;
				n /= 10;
			}
			for (int x = c[0]; x < 10; x++) {
				c[0] = x;
				StringBuilder sb = new StringBuilder();
				for (int j = 0; j < c.length; j++) {
					sb.append(c[j]);
				}
				String k = sb.toString();
				if (!map.containsKey(k)) {
					map.put(k, i2);
				}
			}
		}

		int t = Integer.parseInt(br.readLine());
		PrintWriter pw = new PrintWriter(System.out);
		for (int z = 0; z < t; z++) {
			int n = Integer.parseInt(br.readLine());
			String k = toString(n);
			pw.println(map.getOrDefault(k, -1));
		}
		pw.flush();
		br.close();
	}

	static String toString(int n) {
		int[] c = new int[10];
		while (n > 0) {
			c[n % 10]++;
			n /= 10;
		}
		StringBuilder sb = new StringBuilder();
		for (int j = 0; j < c.length; j++) {
			sb.append(c[j]);
		}
		return sb.toString();
	}
}