#include<bits/stdc++.h>
using namespace std;
#define For(i,a,b) for(int i=(a);i<=(b);i++)
#define Rof(i,a,b) for(int i=(a);i>=(b);i--)
#define wln putchar('\n')
const int N=1005,B=14,MOD=998244353;
int mo(int x){return x>=MOD?x-MOD:x;}
void moplus(int &x,int y){x=mo(x+y);}
int ksm(int a,int b)
{
    int c=1;
    for(;b;b>>=1,a=1ll*a*a%MOD)
        if(b&1)c=1ll*c*a%MOD;
    return c;
}
int getinv(int x){return ksm(x,MOD-2);}
int fac[N],ifac[N],sinv[N];
void math_init(int n)
{
    fac[0]=1;
    For(i,1,n)fac[i]=1ll*fac[i-1]*i%MOD;
    ifac[n]=getinv(fac[n]);
    Rof(i,n,1)ifac[i-1]=1ll*ifac[i]*i%MOD;
    For(i,1,n)sinv[i]=mo(sinv[i-1]+getinv(i));
}
int getC(int a,int b)
{
    if(a<0||b<0||b>a)return 0;
    return 1ll*fac[a]*ifac[b]%MOD*ifac[a-b]%MOD;
}
int n,m,full;
int a[N],b[N],c[1<<B],c1[1<<B],f[N][1<<B],g[N][1<<B],sf1[N][1<<B],sg1[N][1<<B],sg2[N][1<<B];
int main()
{
    scanf("%d%d",&n,&m); full=(1<<m)-1;
    math_init(n);
    For(i,0,m-1)scanf("%d",a+i);
    int st=0;
    For(i,0,m-1)
    {
        scanf("%d",b+i);
        if(b[i]==0)st|=1<<i;
    }
    For(i,0,full)
        For(j,0,m-1)
            if(i>>j&1)c[i]+=a[j]-b[j],c1[i]+=b[j];
    f[0][st]=0; g[0][st]=1;
    int t=n-c[st];
    sg1[0][st]=ifac[t]; sg2[0][st]=1ll*sinv[t]*ifac[t]%MOD;
    For(i,1,c1[full])
        For(j,0,full)
        {
            For(k,0,m-1)
                if(b[k]>0&&(j>>k&1))
                {
                    int jj=j^1<<k,t=n-i-c[jj];
                    int gg=1ll*fac[a[k]]%MOD*ifac[a[k]-b[k]]%MOD*fac[t]%MOD*getC(i-1-c1[jj],b[k]-1)%MOD;
                    moplus(f[i][j],(sf1[i-1][jj]+(sg2[i-1][jj]-1ll*sg1[i-1][jj]*sinv[t]%MOD+MOD)*c[jj])%MOD*gg%MOD);
                    moplus(g[i][j],1ll*sg1[i-1][jj]*gg%MOD);
                }
            int t=n-i-c[j];
            sf1[i][j]=(sf1[i-1][j]+1ll*f[i][j]*ifac[t])%MOD;
            sg1[i][j]=(sg1[i-1][j]+1ll*g[i][j]*ifac[t])%MOD;
            sg2[i][j]=(sg2[i-1][j]+1ll*g[i][j]*sinv[t]%MOD*ifac[t])%MOD;
        }
    printf("%d\n",mo(f[c1[full]][full]+c1[full]));
}