View Code of Problem 27

#include<stdio.h>
#include<math.h>
int main()
{
  int sum,a,b,f,t,i,j,k;
  while(scanf("%d%d",&a,&b)!=EOF)
  {
    if(a>b)
    {
		t=a;
		a=b;
		b=t;
    }
    sum=0;
    for(i=a+1;i<b;i++)
    {
      k=sqrt(i);
      if(i==1)continue;
      f=1;
      for(j=2;j<=k;j++)
		  if(i%j==0){f=0;break;}
      		else f=1;
    if(f==1)
		sum+=i;
	}
    printf("%d\n",sum);
  }
  return 0;
}