V, T, P = map(int, input().split())


def is_ok(time):
    return (P+1) * V + (time-1)//T+1 <= time


def meguru_bisect(ng, ok):
    while (abs(ok - ng) > 1):
        mid = (ok + ng) // 2
        if is_ok(mid):
            ok = mid
        else:
            ng = mid
    return ok


print(meguru_bisect(0, 10**50))