#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for (int i = a; i < b; i++)
using ll = long long;

int main(){
	int a, b;
	cin >> a >> b;
	auto isPrime = []( long long x )
	{
		if( x < 2 ) return false;
		if( x == 2 ) return true;
		if( x % 2 == 0 ) return false;
		for( long long i = 3; i * i <= x; i += 2 ) {
			if( x % i == 0 ) return false;
		}
		return true;
	};
	ll ans = 0;
	rep(x, a, b + 1) {
		if(isPrime(x) == false) continue;
		ll l = x;
		ans += l * l * l - l * l + l + 1;
	}
	cout << ans << endl;
}