//check check check
#include<iostream>
#include<vector>
#include<algorithm>
#include<fstream>
#include<queue>
#include<cstring>
#include<map>
#include<iomanip>

#define ll long long
#define pb(x) push_back(x)

using namespace std;

typedef pair<int,int> ii;

const int NMAX = 1e6+5;

ll phi[NMAX];
bool viz[NMAX];

ifstream fin("mins.in");
ofstream fout("mins.out");

int main()
{
    ll i,j,c,d,a,b;

    fin>>c>>d;

    if(c > d)
        swap(c,d);

    for(i = 1 ; i <= d ; ++i)
        phi[i] = i;

    for(i = 2 ; i <= d ; ++i)
    {
        if(viz[i])
            continue;
        for(j = i ; j <= d ; j += i)
        {
            phi[j] -= phi[j]/i;
            viz[j] = 1;
        }
    }
    ll cntSmall = 0 , cntBig = 0;
    for(i = 1 ; i <= c ; ++i)
        cntSmall += phi[i] , cntBig += phi[i];

    for(i = c+1 ; i <= d ; ++i)
        cntBig += phi[i];

    fout<< ((cntBig + cntSmall)>>1);

    return 0;
}