#include<bits/stdc++.h>
#define el '\n'
#define fi first
#define sc second
#define int ll
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
const int mod=1e9+7;
const int N=1e7+11;
int f[N], a, b;
void sol()
{
cin >> a >> b;
for(int i=1;i<=b;i++) f[i]=i;
for(int i=1;i<=b;i++)
{
for(int j=i*2;j<=b;j+=i) f[j]-=i;
}
int ans=0;
for(int i=a;i<=b;i++) ans+=abs(f[i]);
cout << ans;
}
signed main()
{
// freopen("divisor.INP", "r", stdin);
// freopen("divisor.OUT", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
int t=1;
//cin >> t;
while(t--)
{
sol();
}
}
