#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
const int N = 3000010;
int prime[N], isprime[N];
int phi[N];
void Get_phi()
{
    int i, j, cnt = 0;
    for(i = 2; i < N; i++){
        if(isprime[i] == 0){
            prime[cnt++] = i;
            phi[i] = i-1;
        }    
        for(j = 0; j < cnt && i*prime[j] < N; j++){
            isprime[i*prime[j]]=1;
            if(i%prime[j]==0)
                phi[i*prime[j]]=phi[i]*prime[j];
            else
                phi[i*prime[j]]=phi[i]*(prime[j]-1);
        }
     }     
}  
int main()
{
    int a, b;
    Get_phi();
    while(~scanf("%d %d", &a, &b))
    {
        long long sum = 0;
        for(int i = a; i <= b; i++)
            sum += phi[i];
        cout << sum << endl;
    }
    return 0;
}