#include<bits/stdc++.h>
#define fr(i,j,k) for(register int i=j;i<=k;++i)
#define rf(i,j,k) for(register int i=j;i>=k;--i)
#define foredge(i,j) for(register int i=head[j];i;i=e[i].nxt)
#define pb push_back
#define Times printf("Time:%.3lf\n",clock()/CLOCKS_PER_SEC)
using namespace std;
inline int read(){
	int x=0;
	bool f=0;
	char c=getchar();
	while(!isdigit(c)) f|=(c=='-'),c=getchar();
	while(isdigit(c)) x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return f?-x:x;
}
inline void write(int x){
    if(x<0){putchar('-');x=-x;}
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
inline void writeln(int x){write(x); puts("");}
inline void writepl(int x){write(x); putchar(' ');}
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
inline int randfind(int l,int r){return rnd()%(r-l+1)+l;}
//inline void init(){
//	int t=read();
//	while(t--) work();
//}
const int Maxn=1e3+10,Maxm=(1<<12)+10,mod=998244353;
inline void add(int &x,int y){x+=y;if(x>=mod) x-=mod;}
inline int ksm(int x,int y=mod-2){
    int sum=1;
    while(y){
        if(y&1) sum=1ll*sum*x%mod;
        y=y/2;x=1ll*x*x%mod;
    }
    return sum;
}
int fac[Maxn],ifac[Maxn];
int n,m;
inline int C(int x,int y){
    if(x<y) return 0;
    return 1ll*fac[x]*ifac[y]%mod*ifac[x-y]%mod;
}
int a[Maxn],b[Maxn];
int f[Maxn][Maxm],g[Maxn][Maxm];
int s;
inline void init(){
    n=read();m=read();
    fr(i,1,m) a[i]=read();
    fr(i,1,m) b[i]=read(),s+=b[i];
    fac[0]=ifac[0]=1;
    fr(i,1,n) fac[i]=1ll*fac[i-1]*i%mod,ifac[i]=ksm(fac[i]);
}
int lg[Maxm];
int suma[Maxm],sumb[Maxm];
inline int lowbit(int x){return x&(-x);}
inline void work(){
    fr(i,0,m) lg[1<<i]=i;
    int tmp=0;
    fr(i,1,m) if(b[i]==0) tmp|=(1<<(i-1));
    g[0][tmp]=1;
    int N=(1<<m)-1;
    fr(i,1,N) suma[i]=suma[i-lowbit(i)]+a[lg[lowbit(i)]+1];
    fr(i,1,N) sumb[i]=sumb[i-lowbit(i)]+b[lg[lowbit(i)]+1];
    // fr(i,0,N) cout<<i<<' '<<suma[i]<<' '<<sumb[i]<<endl;
    // cout<<s<<endl;
    // cout<<ksm(16637406)<<endl;
    fr(i,0,s-1) fr(S,0,N){
        if(!f[i][S] && !g[i][S]) continue;
        int in1,in2;
        in1=ksm(n-suma[S]-(i-sumb[S]));
        in2=1ll*(n-i)*ksm(n-suma[S]-(i-sumb[S]))%mod;
        // cout<<i<<' '<<S<<' '<<in1<<' '<<in2<<endl;
        add(f[i+1][S],1ll*g[i][S]*in2%mod*in1%mod);
        add(f[i+1][S],1ll*f[i][S]*in1%mod);
        add(g[i+1][S],1ll*g[i][S]*in1%mod);
        fr(j,1,m){
            if(S&(1<<(j-1))) continue;
            int T=(S|(1<<(j-1)));
            if(sumb[T]>i+1) continue;
            int now=1ll*C(a[j],b[j])*C(i-sumb[S],b[j]-1)%mod*fac[b[j]]%mod;
            add(f[i+1][T],1ll*g[i][S]*in2%mod*now%mod*in1%mod);
            add(f[i+1][T],1ll*f[i][S]*in1%mod*now%mod);
            add(g[i+1][T],1ll*g[i][S]*in1%mod*now%mod);
        }
    }
    // fr(i,1,s) fr(S,0,N) cout<<i<<' '<<S<<' '<<f[i][S]<<' '<<g[i][S]<<endl;
    writeln(f[s][N]);
}
signed main(){
	// freopen("card.in","r",stdin);
	// freopen("card.out","w",stdout);
    init();work();
    // printf("\nTIME:%.3lf",(double)clock()/CLOCKS_PER_SEC);
	return 0;
}