A,B=map(int,input().split())
p=[0]*2+[1]*99
for i in range(2,101):
    if p[i]>0:
        p[i]=i
        for j in range(i+i,101,i):  p[j]=0
pr=[((x-1)*x+1)*x+1 if x>0 else 0 for x in p]
for i in range(1,101):  pr[i]+=pr[i-1]
print(pr[B]-pr[A-1])