a,b=[*map(int,input().split())]
N=b+10
spf=[0]*(N+1)
prime=[]
for m in range(2,N+1):
 if spf[m]<1:spf[m]=m;prime+=[m]
 for p in prime:
  if p>spf[m] or p*m>N:break
  spf[p*m]=p
ans=0
for i in prime:
  if a<=i<=b:
    ans+=i*i*i-i*i+i+1
print(ans)