View Code of Problem 27

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