Q = int(input())

for i in range(Q):
    A, B, C = map(int, input().split())
    
    if C == 1:
        print(-1)
        continue
    
    bit = []
    
    while A >= C:
        bit.append(A%C)
        A //= C
    
    bit.append(A)
    bit.reverse()
    n = len(bit)
    
    if n == 1:
        print(1)
        continue
    
    if bit[0]*C+bit[1] <= 2*C-2:
        if n == 2:
            print(2)
            continue
        
        ope = 3 #足して足してビットシフト
        
        for i in range(2, n):
            if bit[i] != 0:
                ope += 1 #足す
            
            if i < n-1:
                ope += 1 #ビットシフト
    else:
        ope = 0
        
        for i in range(n):
            if bit[i] != 0:
                ope += 1
            
            if i < n-1:
                ope += 1
    
    print(B*ope)