#include<stdio.h>
#include<math.h>
#include<stdint.h>
int main()
{

  int64_t total=2;
  int counter;

  for(int i=3;i<2000000;i+=2)
  {

   counter = 0;
   for(int j=2;j<=sqrt(i);j++)
   {

     if(i%j==0)
     {
         counter++;
    break;
   }


 }

 if(counter==0)
 {
  total=total+i;
 }
  }
 printf("%lld",total);
 return 0;
}