import sys
readline = sys.stdin.readline

Q = int(readline())
Ans = [None]*Q

for qu in range(Q):
    a, b, c = map(int, readline().split())
    if c == 1:
        Ans[qu] = -1
        continue   
    cnt = 0
    twosteps = set(range(c+1, 2*c-1))
    while a > 0:
        if a in twosteps:
            cnt += 2
            a = 0
            continue
        elif a % c:
            a -= a%c
        else:
            a //= c
        cnt += 1
    
    Ans[qu] = b*cnt

print('\n'.join(map(str, Ans)))