#include <stdio.h>
#include <algorithm>
#include <memory.h>
#include <math.h>
#define int long long
int read(int x = 0, int f = 0, char ch = getchar())
{
while ('0' > ch or ch > '9')
f = ch == '-', ch = getchar();
while ('0' <= ch and ch <= '9')
x = x * 10 + (ch ^ 48), ch = getchar();
return f ? -x : x;
}
const int N = 1e7 + 5;
int L, R, ans, f[N];
signed main()
{
// freopen("savrsen.in", "r", stdin), freopen("savrsen.out", "w", stdout);
L = read(), R = read();
for (int d = 1; d <= R; d++)
for (int x = 2LL * d; x <= R; x += d)
f[x] -= d;
for (int i = L; i <= R; i++)
ans += abs(i + f[i]);
return printf("%lld", ans), 0;
}
