import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

a, b = na()
n = 110
f = [1] * n
f[0] = f[1] = 0
for i in range(2, n):
    if f[i]:
        for j in range(2 * i, n, i):
            f[j] = 0

ans = 0
for i in range(a, b + 1):
    if f[i]:
        ans += i * i * i - i * i + i + 1

print(ans)