f ::Int->Int
f n
  |n<2=0
  |n<4=n
  |otherwise=if length [1|e<-[2..(n `div` 2)],n `mod` e==0]>0 then 0 else n

main =do
      e<-getLine
      let x=read e::Int
      print $ sum(take x [f e2|e2<-[1..1000]])