import math
a,b=map(int,input().split())
def p(n):
    if n<2:
        return 0
    for i in range(2,int(math.isqrt(n))+1):
        if n%i==0:
            return 0
    return 1
def f(x):
    return x**3-x**2+x+1
s=0
for x in range(a,b+1):
    if p(x):
        s+=f(x)
print(s)