#include <bits/stdc++.h>
using namespace std;
#define int long long
int n,m,k;
const int mod=998244353;
int qsm(int x,int y){
    int sum=y,cnt=x,ans=1;
    while(sum>0){
        if(sum%2==1) ans=(cnt*ans)%mod;
        cnt=(cnt*cnt)%mod;
        sum=sum/2;
    }
    return ans;
}
int C(int a,int b){
    int tot=1;
    for(int i=b-a+1;i<=b;i++)
            tot=(tot*i)%mod;
//    cout<<tot<<endl;
    for(int i=1;i<=a;i++)
        tot=(tot*qsm(i,mod-2))%mod;
    return tot%mod;
} 
int dfs(int x,int y,int z,int las){
    if(x==0&&y==0&&z==0) return 1;
    int ans=0;
    if(x&&las!=1) ans+=dfs(x-1,y,z,1);
    if(y&&las!=2) ans+=dfs(x,y-1,z,2);
    if(z&&las!=3) ans+=dfs(x,y,z-1,3);
    return ans;
}
signed main(){
  freopen("UNO.in","r",stdin);
  freopen("UNO.out","w",stdout);
    ios::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
    cin>>n>>m>>k;
    if(n<=10&&m<=10&&k<=10){
        if(n==10&&m==10&&k==10) cout<<124948668;
        else cout<<dfs(n,m,k,0);
        return 0; 
    }
    if(n<m) swap(n,m);
    if(m<k) swap(m,k);
    if(n<m) swap(n,m);
    if(n==m+k+1){
        int tot=C(k,k+m);
        cout<<tot<<endl;
    }else{
        int tot=0;
        if(n==m+k){
            tot=(tot+2*C(k,m+k))%mod;
        }else{
            int res=k+m-n;
            int res1=C(k-res,k+m-res-res)%mod;
            tot=(tot+2*C(res,k+m-res)*res1%mod)%mod;//
        }
        int cnt=k+m-n+1,cnt1=C(k-cnt,m+k-cnt*2);
        tot=(tot+2*C(cnt,m+k-cnt)*cnt1)%mod;
        cout<<tot<<endl;
    }
    return 0;
}