def main():
    N = int(input())

    for i in range(N - 100, N + 101):
        if not is_prime(i) and i > 1:
            print(i)
            break

def is_prime(n):
    if n == 2:
        return True
    if n < 2 or not n & 1:
        return False

    for i in range(3, n, 2):
        if not n % i:
            return False
        if i * i >= n:
            break
    return True

main()