package main

import . "fmt"
import . "math/big"

func main() {
	var a,b,s int64
	Scan(&a, &b)
	for x:=a; x<=b; x++ {
		if NewInt(x).ProbablyPrime(0) {
			s += x*x*x-x*x+x+1
		}
	}
	Println(s)
}