#include<bits/stdc++.h>
#define mod 1000003
using namespace std;
int n,m,x,ras,a[100001];
int main()
{
    freopen("grigo.in","r",stdin);
    freopen("grigo.out","w",stdout);
    scanf("%d %d",&n,&m);
    for(int i = 1; i <= m; i ++)
        scanf("%d",&x), a[x] = 1;
    ras = 1;
    for(int i = 1; i <= n; i ++)
        if(a[i] == 0)
            ras = 1LL * ras * (i-1) % mod;
    printf("%d",ras);
    return 0;
}