View Code of Problem 27

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