View Code of Problem 27

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