def pr(n):
    if n<=1:
        return False
    if n<=3:
        return True
    if (n%2==0) or (n%3==0):
        return False
    i=5
    while i*i<=n:
        if (n%i==0) or (n%(i+2)==0):
            return False
        i+=6
    return True
def f(x):
    return (x**3)-(x**2)+x+1
a,b=map(int,input().split())
print(sum(f(i) for i in range(a,b+1) if pr(i)))