a,b = map(int,input().split())
sosuu = []
ans = 0
if a == 1 and b == 1:
    print(0)
    exit()
sosuulist = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]
ok = False
if a == b:
    for i in sosuulist:
        if a == i:
            ok = True
            break
if ok:
    x = a
    ans = (x**3)-(x**2)+(x**1)+1
    print(ans)
    exit()
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)