View Code of Problem 27

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