View Code of Problem 27

#include <stdio.h>
#include <stdlib.h>

int main(){
	int a,b;
	while(scanf("%d %d",&a,&b)!=EOF){
		int i,j,sum=0;
		for(i=a+1;i<b;i++){
			int flag=1;
			for(j=2;j<i;j++){
				if(i%j==0){
					flag=0;
					break;
				} 
			}
			if(flag==1) 
			sum+=i;
		}
		printf("%d\n",sum);
	}

}