#include <stdio.h>
int main()
{ long long int x,n,m,i,ok[100005];

freopen("grigo.in","r",stdin);
freopen("grigo.out","w",stdout);
scanf("%lld %lld",&n,&m);
for (i=1;i<=n;i++) ok[i]=0;scanf("/n");
for  (i=1;i<=m;i++) {scanf("%lld",&x);ok[x]=1;}
x=1;
for (i=1;i<=n;i++) if (!ok[i]) x=(x*(i-1))%1000003;
printf("%lld",x);

	return 0;}