zerojudge a121

#include <bits/stdc++.h>
using namespace std;

int findprime(int x)
{
    int check=1;
    for(int i=3;i<sqrt(x)+1;i+=2)
        if(x%i==0)
        {
            check=0;
            break;
        }
    return check;
}

int main()
{
    int a,b;
    while(cin>>a>>b)
    {
        int count=0,A[5]={2,3,5,7,11};
        for(int i=a;i<=b;++i)
            if(!(!(i%2)||!(i%3)||!(i%5)||!(i%7)||!(i%11))&&i!=1)
                count+=findprime(i);
        for(int i=0;i<5;++i)
            if(a<=A[i]&&A[i]<=b)
                ++count;
        cout<<count<<endl;
    }
    return 0;
}