#python

def IsPrime(n):

   _divider = 2

   while _divider**2 <= n and n % _divider != 0:

       _divider += 1

   return _divider**2 > n

_sum, i, _counter = 0, 1, 0

N = int(input("N="))

while _counter < N:

   if IsPrime(i):

       _sum += i

       _counter += 1

   i += 1

print(f"SUM =", _sum)