#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<cmath>
#define N 2000009
#define p 998244353
#define ll long long
using namespace std;

inline int power(int a,int t){
	int res = 1;
	while(t){
		if(t&1) res = (ll)res*a%p;
		a = (ll)a*a%p;
		t >>= 1;
	}
	return res;
}

int fac[N],ifac[N],inv[N];

void init(int n){
	inv[1] = fac[0] = fac[1] = ifac[0] = ifac[1] = 1;
	for(int i=2;i<=n;++i) fac[i] = (ll)fac[i-1]*i%p;
	ifac[n] = power(fac[n],p-2);
	for(int i=n-1;i;--i) ifac[i] = (ll)ifac[i+1]*(i+1)%p;
	for(int i=2;i<=n;++i) inv[i] = (ll)fac[i-1]*ifac[i]%p;
}

inline int binom(int n,int m){
	if(n<m||m<0) return 0;
	return (ll)fac[n]*ifac[m]%p*ifac[n-m]%p;
}

inline int dfac(int n){
	int res = 1;
	for(int i=n;i>0;i-=2) res = (ll)res*i%p;
	return res;
}

int a,b,t;
int f[N];

int main(){
	init(2000003);
	scanf("%d%d%d",&a,&b,&t);
	if(t%2==1 || (b-a)*2>t){
		puts("0");
		return 0;
	}
	b -= a,t /= 2;
	if(b>=0){
		f[0] = (ll)binom(t,b)*dfac(2*t-1)%p;
		f[1] = ((-1-b)-(ll)(1+t)*t)%p*f[0]%p;
		f[1] = -(ll)f[1]*inv[b+1]%p;
		for(int i=2;i<=a;++i){
			int tmp = (2ll*(1-b-i)*i + (b-1)-(ll)(1+t)*t)%p*f[i-1]%p;
			tmp = (tmp + ((ll)i*(i+b-2)+(1-b))%p*f[i-2])%p;
			f[i] = -(ll)tmp*inv[i]%p*inv[i+b]%p;
		}
		printf("%d",(f[a]+p)%p);
	}else{
		f[-b] = (ll)binom(t,-b)*dfac(2*t-1)%p;
		for(int i=-b+1;i<=a;++i){
			int tmp = (2ll*(1-b-i)*i + (b-1)-(ll)(1+t)*t)%p*f[i-1]%p;
			tmp = (tmp + ((ll)i*(i+b-2)+(1-b))%p*f[i-2])%p;
			f[i] = -(ll)tmp*inv[i]%p*inv[i+b]%p;
		}
		printf("%d",(f[a]+p)%p);
	}
	return 0;	
}