View Code of Problem 27

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

return 0;
}