from collections import defaultdict
T=int(input())
D=defaultdict(int)
Z=defaultdict(int)
for i in range(1,31623):
    C=[0 for _ in range(10)]
    A=list(str(i**2))
    for a in A:
        C[int(a)]+=1
    if tuple(C[1:]) not in D:
        D[tuple(C[1:])]=i**2
        Z[i**2]=C[0]
for _ in range(T):
    N=list(input())
    C=[0 for _ in range(10)]
    for n in N:
        C[int(n)]+=1
    ans=-1
    if tuple(C[1:]) in D and C[0]>=Z[D[tuple(C[1:])]]:
        ans=D[tuple(C[1:])]
    print(ans)