n = int(input())
l = max(2, n-100)
r = n+100

def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    return divisors

for i in range(l, r+1):
    d = make_divisors(i)
    if len(d) > 2:
        print(i)
        exit()