#include <bits/stdc++.h>
using namespace std;
const int MOD = 998244353;
const int MAXN = 5010;
int _w;
int a, b, c;
void add_mod(int &a, int b) { a = (a + b) % MOD; }
int f[MAXN][MAXN];
int solve(int n, int m) {
  memset(f, 0, sizeof f);
  f[0][m] = 1;
  for (int i = 0; i < n; ++i)
    for (int j = 0; j <= m; ++j) {
      add_mod(f[i + 1][j], f[i][j]);
      if (j) add_mod(f[i + 1][j - 1], int((long long)f[i][j] * j % MOD));
    }
  int ans = 0;
  for (int i = 0; i <= m; ++i) add_mod(ans, f[n][i]);
  return ans;
}
int main() {
  _w = scanf("%d%d%d", &a, &b, &c);
  long long ans = solve(a, b);
  ans = ans * solve(a, c) % MOD;
  ans = ans * solve(b, c) % MOD;
  printf("%lld\n", ans);
  return 0;
}
