#include <stdio.h>
#include <stdlib.h>
#define MOD 1000003
int v[100001];
int main()
{
    int n,m,i,rez,x;
    freopen("grigo.in","r",stdin);
    freopen("grigo.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(i=0; i<m; i++)
    {
        scanf("%d",&x);
        v[x-1]=1;
    }
    rez=1;
    for(i=1; i<n; i++)
        if(1-v[i])
            rez=(rez*i)%MOD;
    printf("%d\n",rez);

    return 0;
}