def prime(x):
    if (x <= 1): return False
    if (x % 2 == 0): return x == 2
    if (x % 3 == 0): return x == 3
    i = 5
    while (i * i <= x):
        if (x % i == 0): return False
        if (x % (i + 2) == 0): return False
        i += 6
    return True

n = int(input())
while prime(n) == False: n += 1
print(n)

from math import sqrt
from math import trunc

n = int(input())

prime = [True for i in range(1000000 + 1)]

def sieve():
    prime[0] = prime[1] = False
    for i in range(2, 1001):
        if prime[i]:
            for j in range(i * i, 1000000 + 1, i):
                prime[j] = False

sieve()

while prime[n] == False:
    n += 1

print(n)