$2.$ The RSA algorithm is based in the problem of factorization, which relies in the computing difficulty of obtaining two prime numbers p and q given their product n$.$ If n was $55,$ what the value of the prime numbers would be$?$ And if n was $143?$ You probably found out by brute$-$forcing, that is$,$ just trying combinations. That is why p and q must be large enough in cryptosystems.