q = int(input())
abc = [[int(i) for i in input().split()] for j in range(q)]
ans = 0
for i in range(q):
    a,b,c = abc[i]
    num = a
    ans = 0
    if c == 1:
        print(-1)
        continue
    while num > 0:
        if num <= 1*(c-1):
            ans += 1
            break
        elif num <= 2*(c-1):
            ans += 2
            break
        if num%c != 0:
            ans += 1
        num = (num//c)*c
        ans += 1
        #print(num)
        num = num//c
        #print(num,ans)
    #print((987654321//57)*57)
    #print(987654321//57)
    print(ans*b)