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

def is_ok(time):
    # 整数を買えればTrueを返す
    return time-V*P-time//T <= V

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(10**20 + 1, 0)+1)