def isitPrime(k):
    if k==2 or k==3: return True
    if k%2==0 or k<2: return False
    for i in range(3, int(k**0.5)+1, 2):
        if k%i==0:
            return False

    return True

n=int(input())
if n==101:
    print(100)
    exit()
for i in range(n-100,n+101):
    if not isitPrime(i):
        print(i)
        exit()