Eratostene0

#include <fstream>
#define N 1000001
using namespace std;
long long int SD[N];

void Ciur_SD()
{
    int j;
    SD[1]=1;
    for(int i=2;i<N;++i)
    {
            SD[i]+=i+1,SD[i]+=SD[i-1],j=i+i;
            while(j<N)
                    SD[j]+=i,j+=i;
    }
}

int main()
{
    int n;
    ifstream f("eratostene0.in");
    f>>n;
    int x,y;
    Ciur_SD();
    ofstream g("eratostene0.out");
    while(n--)
        f>>x>>y,g<<SD[y]-SD[x-1]<<'\n';
    return 0;
}