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#include <iostream>
#include <vector>
#define MOD 998244353
typedef long long ll;

using namespace std;
vector<ll> factorial, inv_factorial;


ll mod_pow(ll base, ll exp, ll mod) {
    ll result = 1;
    while (exp > 0) {
        if (exp % 2 == 1)
            result = (result * base) % mod;
        base = (base * base) % mod;
        exp /= 2;
    }
    return result;
}


void precompute_factorials(int n) {
    factorial.resize(n + 1);
    inv_factorial.resize(n + 1);
    factorial[0] = 1;
    for (int i = 1; i <= n; ++i) {
        factorial[i] = factorial[i - 1] * i % MOD;
    }
    inv_factorial[n] = mod_pow(factorial[n], MOD - 2, MOD); 
    for (int i = n - 1; i >= 0; --i) {
        inv_factorial[i] = inv_factorial[i + 1] * (i + 1) % MOD;
    }
}


ll binomial_coefficient(int n, int k) {
    if (k > n || k < 0) return 0;
    return factorial[n] * inv_factorial[k] % MOD * inv_factorial[n - k] % MOD;
}

int main() {
    int X, Y, Z;
    std::cin >> X >> Y >> Z;
    int sum = X + Y + Z;
    precompute_factorials(sum);  


    ll result = binomial_coefficient(sum, X);
    result = result * binomial_coefficient(sum - X, Y) % MOD;
    cout << result << endl;

    return 0;
}

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