import sys def input(): return sys.stdin.readline().strip() def list2d(a, b, c): return [[c] * b for i in range(a)] def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)] def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)] def ceil(x, y=1): return int(-(-x // y)) def INT(): return int(input()) def MAP(): return map(int, input().split()) def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)] def Yes(): print('Yes') def No(): print('No') def YES(): print('YES') def NO(): print('NO') sys.setrecursionlimit(10 ** 9) INF = 10 ** 19 MOD = 10 ** 9 + 7 EPS = 10 ** -10 def bfs(src): from collections import deque que = deque([src]) dist = {} dist[src] = 0 while que: u = que.popleft() if u % c == 0: v = u // c if v not in dist: dist[v] = dist[u] + b que.append(v) else: v = u // c * c if v not in dist: dist[v] = dist[u] + b que.append(v) if u < c*2 and u - (c-1) >= 0: v = u - (c-1) if v not in dist: dist[v] = dist[u] + b que.append(v) return dist for _ in range(INT()): a, b, c = MAP() if c == 1: print(-1) continue res = bfs(a) if 0 in res: print(res[0]) else: print(-1)