n = int(input())
a = []
sosu = []

def sosuuhantei(x):
    p = x
    if p < 2:
        return false
    elif  n == 2:
        return p
    else:
        for i in range(3,math.floor(math.sqrt(x)) + 1,2):
            if x % i == 0:
                return False
        else:
             return x
            
            
sosulist = []
 
if n < 2:
    None
elif n == 2:
    sosulist.append(2)
else:
    sosulist.append(2)
    for i in range(3,55555+1,2):
        sosulist.append(sosuuhantei(i))
import random
print(random.choice(sosulist,k = 5))
    