def discrete_logarithm(a,b,MOD,permit0):
    a %= MOD; b %= MOD
    q = int(MOD**0.5)+2
    # baby-step
    h = 1 if MOD != 1 else 0 
    memo = {}
    for i in range(q):
        if h==b and (permit0 or i): return i
        memo[h*b%MOD] = i
        h = h*a%MOD
    # giant-step #ここに来た時 h = a^q
    g = h
    for i in range(q):
        if g in memo:
            res = (i+1)*q-memo[g]
            if pow(a,res,MOD) == b: return res
            else: return -1
        g = g*h%MOD
        
    return -1 #見つからない場合


T,*a = map(int,open(0).read().split())
for ai in a:
    while ai%2==0: ai//=2
    while ai%5==0: ai//=5
    print(discrete_logarithm(10,1,ai,0))