dic = {}
a = b = c = 0

def dfs(x):
    global dic,b,c
    if x == 0:
        return 0
    if x in dic:
        return dic[x]

    c1 = (x+c-2)//(c-1)*b
    c2 = b+dfs(x//c)
    if x%c:
        c2 += b
    dic[x] = min(c1,c2)
    return dic[x]
        
def solve():
    global dic,a,b,c
    a,b,c = map(int,input().split())
    if c == 1:
        return -1

    dic = {}
    return dfs(a)

q = int(input())
for _ in range(q):
    print(solve())