#include <bits/stdc++.h>
using namespace std;
#define in long long
#define int __int128
#define mod (__int128)998244353

signed main() {
	in aa, bb, cc, ee, ff, dd;
	cin >> aa >> bb >> cc >> ee >> dd >> ff;
	int a, b, c, d, e, f;
	a = aa % mod;
	b = bb % mod;
	c = cc % mod;
	d = dd % mod;
	e = ee % mod;
	f = ff % mod;
	in ans = ((a * b % mod) * c % mod - (e * d) % mod * f % mod) % mod;
	cout << ans;
	return 0;
}