from itertools import permutations
import math
T=int(input())
for _ in range(T):
    N=list(input())
    C=[0 for _ in range(10)]
    for n in N:
        C[int(n)]+=1
    ans=-1
    for i in range(1,31623):
        A=list(str(i**2))
        D=[0 for _ in range(10)]
        for a in A:
            D[int(a)]+=1
        if C[1:]==D[1:] and C[0]>=D[0]:
            ans=i**2
            break
    print(ans)