Given the task definition and input, reply with output. You are given a sentence in Polish. Your job is to translate the Polish sentence into Arabic.

Więc jeśli myślimy o ich mobilności, potrzebujemy sprawnej komunikacji.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
إذن عندما تفكر في تحريك هؤلاء الناس فإنك تفكر في وسائل مواصلات عالية الكثافة