View Code of Problem 27

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