View Code of Problem 27

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