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

//#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target("avx,avx2,fma")

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;
#define MP make_pair
#define PB push_back
#define X first
#define Y second

#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define RFOR(i, b, a) for(int i = (b) - 1; i >= (a); --i)
#define ALL(a) a.begin(), a.end()
#define SZ(a) (int)((a).size())
#define FILL(a, value) memset(a, value, sizeof(a))
#define debug(a) cerr << #a << " = " << a << endl;

template<typename T> void setmax(T& x, T y) {x = max(x, y);}
template<typename T> void setmin(T& x, T y) {x = min(x, y);}

template<typename T> void print(const T& a, ostream& out){	
	for(auto i: a) out << i << ' ';
	out << endl;
}

const double PI = acos(-1.0);
const LL INF = 1e9 + 47;
const LL LINF = INF * INF;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

namespace IntModulo
{
	const int mod = 998244353;

	inline int add(int x, int y, int m = mod)
	{
		if (x + y < m)
			return x + y;
		return x + y - m;
	}

	inline int sub(int x, int y, int m = mod)
	{
		if (x >= y)
			return x - y;
		return x - y + m;
	}

	inline int mult(int x, int y, int m = mod)
	{
		return x * (LL) y % m;
	}

	inline int power(int x, LL y, int m = mod)
	{
		int r = 1;
		while(y)
		{
			if (y & 1)
				r = mult(r, x, m);
			x = mult(x, x, m);
			y >>= 1;
		}
		
		return r;
	}
	
	inline int inverse(int x, int m = mod)
	{
		return power(x, m - 2, m);
	}

	inline void ADD(int& x, int y, int m = mod){
		x += y;
		if (x >= m) x -= m;
	}

	inline void SUB(int& x, int y, int m = mod){
		x -= y;
		if (x < 0) x += m;
	}

	inline void MULT(int& x, int y, int m = mod){
		x = (x * (LL) y) % m;
	}
};

using namespace IntModulo;


int main()
{
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

	int n = 3;
	int ans = 1;
	while(n--){
		LL x; cin >> x;
		MULT(ans, x * (x + 1) / 2 % mod);
	}

	cout << ans << endl;
    cerr << "Time elapsed: " << clock() / (double)CLOCKS_PER_SEC << endl;
    return 0;
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <iomanip>
#include <utility>
#include <tuple>
#include <functional>
#include <bitset>
#include <cassert>
#include <complex>
#include <stdio.h>
#include <time.h>
#include <numeric>
#include <random>
#include <unordered_map>
#include <unordered_set>
#define all(a) a.begin(),a.end()
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define pb push_back
#define debug(x) cerr << __LINE__ << ' ' << #x << ':' << (x) << '\n'
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> P;
typedef complex<ld> com;
template<class T> using prique = priority_queue<T, vector<T>, greater<T>>;
constexpr int inf = 1000000010;
constexpr ll INF = 1000000000000000010;
constexpr int mod1e9 = 1000000007;
constexpr int mod998 = 998244353;
constexpr ld eps = 1e-12;
constexpr ld pi = 3.141592653589793238;
constexpr ll ten(int n) { return n ? 10 * ten(n - 1) : 1; };
int dx[] = { 1,0,-1,0,1,1,-1,-1 }; int dy[] = { 0,1,0,-1,1,-1,1,-1 };
void fail() { cout << "-1\n"; exit(0); } void no() { cout << "No\n"; exit(0); }
template<class T, class U> inline bool chmax(T &a, const U &b) { if (a < b) { a = b; return true; } return false; }
template<class T, class U> inline bool chmin(T &a, const U &b) { if (a > b) { a = b; return true; } return false; }
template<class T> istream &operator >> (istream &s, vector<T> &v) { for (auto &e : v) s >> e; return s; }
template<class T> ostream &operator << (ostream &s, const vector<T> &v) { for (auto &e : v) s << e << ' '; return s; }

struct fastio {
	fastio() {
		cin.tie(0); cout.tie(0);
		ios::sync_with_stdio(false);
		cout << fixed << setprecision(20);
		cerr << fixed << setprecision(20);
	}
}fastio_;

int main() {
	ll ans = 0;
	ll n;
	cin >> n;
	rep(_, n) {
		ll a, b;
		cin >> a >> b;
		ans += (a + b) * (b - a + 1) / 2;
	}
	cout << ans << '\n';
}