n = int(input())
lst = [0 for i in range(400000)]
num = 0
if n == 1:
    print(2)
else:
    for i in range(2, 400000):
        e = 0# 要找的数i
        if i%2 != 0:
            for j in range(2, 400000):
                if j * j <= i:
                    if i % j == 0:
                        e = 1
                        break
                else:
                    break
            if e == 0:
                lst[num] = i
                num = num + 1
        if num > n:
             break
    print(lst[n-2])