V, T, P = map(int, input().split())
VP1 = V * (P + 1)

ub = 10 ** 20
lb = 0
while ub - lb > 1:
    mid = (ub + lb) // 2
    if -(-mid // T) + VP1 <= mid:
        ub = mid
    else:
        lb = mid
print(ub)