#include<bits/stdc++.h>
#define For(i,j,k) for(int i=(j);i<=(k);++i)
#define ForDown(i,j,k) for(int i=(j);i>=(k);--i)
#define Debug(fmt, args...) fprintf(stderr,"(func %s, line #%d): " fmt,__func__,__LINE__,##args),fflush(stderr)
#define debug(fmt, args...) fprintf(stderr,fmt,##args),fflush(stderr)
#define within :
#define LJY main
using namespace std;
typedef long long ll;
const int N=1e7+5,mod=998244353;
ll ksm(ll a,int k){ll s=1;while(k){if(k&1) s=s*a%mod;a=a*a%mod;k>>=1;}return s;}
mt19937 rnd(chrono::system_clock::now().time_since_epoch().count());
inline int read(){
  char ch=getchar();int x=0,f=1;
  while(ch<'0'||ch>'9'){if(ch=='-') f=-1;ch=getchar();}
  while(ch>='0'&&ch<='9')
    x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
  return x*f;
}
int fac[N],inv[N];
void reduce(int&x){x+=(x>>31)&mod;}
int calc(int x,int y){
  if(x<0||y<0) return 0;
  return (ll)fac[x+y]*inv[x]%mod*inv[y]%mod;
}
int f(int n,int m,int b,int c){
  int res=calc(n,m),x=n,y=m;
  while(x>=0&&y>=0){
    swap(x,y);x-=b;y+=b;reduce(res-=calc(x,y));
    swap(x,y);x-=c;y+=c;reduce(res+=calc(x,y)-mod);
  }x=n,y=m;
  while(x>=0&&y>=0){
    swap(x,y);x-=c;y+=c;reduce(res-=calc(x,y));
    swap(x,y);x-=b;y+=b;reduce(res+=calc(x,y)-mod);
  }return res;
}
signed LJY(){
  fac[0]=1;For(i,1,N-1) fac[i]=(ll)fac[i-1]*i%mod;
  inv[N-1]=ksm(fac[N-1],mod-2);
  ForDown(i,N-1,1) inv[i-1]=(ll)inv[i]*i%mod;
  int n=read(),m=read(),ans=0;
  For(i,0,(m+1)/2) if((i&1)==(n&1))
    reduce(ans+=f((n-i)/2,(n+i)/2-1,-2,(m+1)/2)-mod);
  printf("%lld\n",ans);
  return 0;
}