#include<stdio.h>
#define MOD 1000003
int v[100002];

int main()
{
    freopen("grigo.in","r",stdin);
    freopen("grigo.out","w",stdout);
    int n,m,i,s=1,x;
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;++i)
    {
        scanf("%d",&x);
        v[x]=1;
    }

    for(i=2;i<=n;++i)
        if(!v[i])
            s=(1LL*s*(i-1))%MOD;
    printf("%d\n",s);

    return 0;
}