A, B = map(int, input().split())
t = 0
L = []
M = range(A,B+1)
for n in M :
    sushu = True
    for b in range(2,n) :
        if n % b == 0:
            sushu = False
            break
    if sushu:
        L.append(n)
for x in L :
    y = x ** 3 - x ** 2 + x + 1
    t = t + y 
print(t)