#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(),x.end()
const ll MAXN=1e7+5,MOD=1e9+7,INF=1e18,LG=16,MAX=1e7;
ll i,n,m,j,k,p,t,a[MAXN],nt[MAXN],luu[MAXN];
int main(){
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
ll l,r;
cin>>l>>r;
for(i=2;i<=MAX;i++){
if(!nt[i]){
for(j=i;j<=MAX;j+=i)
nt[j]=i;
}
}
luu[1]=1;
for(i=2;i<=r;i++){
ll cur=nt[i];
ll x=i/cur;
m=i;
while(m%cur==0){
m/=cur;
}
if(x%cur==0){
luu[i]=luu[x]*(i/m*cur-1)/(i/m-1);
}
else luu[i]=luu[x]*(i/m*cur-1)/(cur-1);
}
ll ans=0;
for(i=l;i<=r;i++){
ans+=2*i-luu[i];
}
cout<<ans;
}
