primeNumbers

#!/usr/bin/python2
# -*- coding: utf-8 -*-

n = int(raw_input('Podaj dowolną liczbe: '))
s = 0
for i in xrange(2, n+1):
    for j in xrange(2, int(i**0.5)+1):
        if i % j == 0:
            break
    else:
        s += i
print s