a,b = map(int,input().split())
sosuu = []
ans = 0
for i in range(a,b+1):
    ok = True
    for j in range(2,i):
        if i%j == 0:
            ok = False
            break
    if ok:
        sosuu.append(i)
for x in sosuu:
    ans += x**3-x**2+x**1+1
print(ans)