#include<bits/stdc++.h>
using namespace std;
const int mod=998244353;
void add(int &x,const int y){x=((x+y>=mod)?(x+y-mod):(x+y));}
void sub(int &x,const int y){x=((x>=y)?(x-y):(x+mod-y));}
int mul(int x,int y){return 1ll*x*y%mod;}
int qpow(int a,int b){
	int c=1;
	while(b){
		if(b&1)c=mul(c,a);
		a=mul(a,a),b>>=1;
	}return c;
}
int a,b,c,fac[30005],ifac[30005],Prod[30005],iProd[30005],inv[30005],pw[30005];
int C(int n,int m){return mul(mul(fac[n],ifac[m]),ifac[n-m]);}
int calc(int n,int k){
	return 1ll*pw[n]*(k+k+1)%mod*inv[n+k+1]%mod*inv[n+n+k+k+1]%mod*C(k+k,k)%mod*C(n+n+n+k+k,n)%mod;
}
int f(int a,int b){a-=b;return calc(b,a);}
int g(int a,int b,int c){return mul(fac[a+b+c],mul(ifac[a],mul(ifac[b],ifac[c])));}
int A[10005][10005];
int main(){
	ifac[0]=fac[0]=Prod[0]=iProd[0]=1,pw[0]=1;
	for(int i=1;i<=30000;++i){
		fac[i]=mul(i,fac[i-1]),ifac[i]=qpow(fac[i],mod-2),inv[i]=qpow(i,mod-2),pw[i]=pw[i-1]*4ll%mod;
		int x=mul(2*i,qpow(2*i+1,mod-2));
		Prod[i]=mul(Prod[i-1],x),iProd[i]=qpow(Prod[i],mod-2);
	}
	cin>>a>>b>>c;
	for(int i=0;i<=max(b-1,c-1);++i)for(int j=0;j<=i;++j)A[i][j]=f(i,j);
	int Ans=g(a,b,c);
	for(int i=0;i<=min(a,b-1);++i)
	  for(int j=0;j<=min(i,c);++j)sub(Ans,mul(A[i][j],g(a-i,b-1-i,c-j)));
	for(int i=0;i<=min(a,c-1);++i)
	  for(int j=0;j<=min(i,b);++j)sub(Ans,mul(A[i][j],g(a-i,b-j,c-1-i)));
	cout<<Ans;
	return 0;
}