View Code of Problem 27

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