#include int fun(int n){int i,k=0;for(i=2;i<=n/2;i++)if(n%i==0) break;if(i>n/2&&n>1) k=1;return k;}void main(){int i,n,s=0;scanf("%d",&n);for(i=1;i<=n;i++)if(fun(i)) s+=i;printf("%d",s);}
