#include <bits/stdc++.h>
using namespace std;
/*
#include <ext/pb_ds/priority_queue.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
__gnu_pbds::tree<std::pair<int, int>, __gnu_pbds::null_type,
                 std::less<std::pair<int, int>>, __gnu_pbds::rb_tree_tag,
                 __gnu_pbds::tree_order_statistics_node_update>
    trr;
using namespace __gnu_cxx;
//*/
#define ll long long
#define pi pair<ll, ll>
#define fi first
#define se second
#define mod 998244353ll
//#define inv2 (mod - mod / 2)
#define inv2 499122177
#define N 11111111
ll cnt[N], sum, ans;
int main()
{
	ll l, r;
	cin >> l >> r;
	for(int i = 1 ; i <= r ; i++){
		if(i == 1){
			cnt[i] = 2;
		}
		else if(i % 2 == 0)
			cnt[i] = cnt[i / 2];
		else
			cnt[i] = ((cnt[i / 2] + cnt[i / 2 + 1]) * inv2 % mod + 1) % mod;
		sum = (cnt[i] + sum) % mod;
		if(i == l - 1)
			ans = sum;
		//cerr << cnt[i] << " ";
	}
	cout << (sum - ans + mod) % mod;
	return 0;
}