def f(x): return x*x*x-x*x+x+1
def prime(a):
    if a == 1: return False
    for i in range(2,a):
        if a%i == 0: return False
    return True
x,y = map(int,input().split())
print(sum(f(a) for a in range(x,y+1) if prime(a)))