#include<bits/stdc++.h>
using namespace std;
#define ll unsigned long long
ll a,b,s1,s2;
int main()
{
    cin>>a>>b;
    a--;
    for(ll i=1; i<=a; i=a/(a/i)+1)
        s1+=(a/i)*(a/(a/i)-i+1)*(a/(a/i)+i)/2;
    for(ll i=1; i<=b; i=b/(b/i)+1)
        s2+=(b/i)*(b/(b/i)-i+1)*(b/(b/i)+i)/2;
    cout<<s2-s1<<endl;
    return 0;
}
 

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