View Code of Problem 27

#include<stdio.h>
#include<math.h>
int isprime(int a)
{
	int i,flag=1;
	if(a==1) flag = 0;
	else if(a>1)
	{
		for(i=2;i<=sqrt(a);i++)
		{
			if(a%i==0)
			{
				flag = 0;
				break;
			}
		}
	}
	return flag;
}
int main()
{
	int a,b;
	int i,t;
	int sum;
	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(isprime(i))
	     	sum += i;
	   }
	   printf("%d\n",sum);
	}
	return 0;
}