A,B=map(int, input().split())
c=200
D=[1]*c
D[0]=0
D[1]=0
for i in range(2,c):
  if D[i]==1:
    d=i
    while d+i<c:
      d+=i
      D[d]=0
      
ans=0
for i in range(A,B+1):
  if D[i]==1:
    ans+=i**3-i**2+i+1 
print(ans)