#include<bits/stdc++.h>
using namespace std;
#include<atcoder/modint>
typedef atcoder::modint998244353 mint;
typedef long long ll;

const mint inv2 = mint(2).inv();

mint solve(ll n) {
	mint ans = 0;
	for (ll b=1; b*b<=n; b++) {
		ll num = max(0LL, n - b*b + 1);
		ll q = num / b;
		ll r = num % b;
		ans += mint(b) * (b - 1) * inv2 * q;
		ans += mint(r) * (r - 1) * inv2;
	}

	for (ll k=1; k*k<=n; k++) {
		ll l = k + 1;
		ll r = (n-1) / k;
		if (r - l < 0) continue;
		ans += mint(r - l) * k * (k + 1) * inv2;
		ll lt = r * k + 1;
		ll rt = n;
		ans += mint(rt - lt + 1) * (rt - lt + 2) * inv2;
	}

	return ans;
}

int main() {
	ll n; cin >> n;
	cout << solve(n).val() << '\n';
}