#include <fstream>

using namespace std;

const char InFile[]="grigo.in";
const char OutFile[]="grigo.out";
const int MaxN=100111;
const int MOD=1000003;

ifstream fin(InFile);
ofstream fout(OutFile);

int N,M,sol;
char _fixed[MaxN];

int main()
{
	fin>>N>>M;
	for(register int i=1;i<=M;++i)
	{
		fin>>sol;
		_fixed[sol]=1;
	}
	fin.close();
	
	if(!_fixed[1])
	{
		sol=0;
	}
	else
	{
		sol=1;
		for(register int i=2;i<=N;++i)
		{
			if(!_fixed[i])
			{
				sol=(1LL*sol*(i-1))%MOD;
			}
		}
	}
	
	fout<<sol;
	fout.close();
	return 0;
}