View Code of Problem 27

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