#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
#define INF (1<<30)
#define INFLL (1ll<<60)
typedef pair<int, int> P;
typedef pair<int, P> E;
#define MOD (1000000007ll)
#define l_ength size

void mul_mod(ll& a, ll b){
	a *= b;
	a %= MOD;
}

void add_mod(ll& a, ll b){
	a += b;
	if(a>MOD){
		a -= MOD;
	}
}

bool done[100100];
ll memo[100100];
int k,x[100100];

ll solve(int p){
	int i;
	if(done[p]){
		return memo[p];
	}
	done[p] = true;
	if(!p){
		memo[p] = 1ll;
		return memo[p];
	}
	for(i=0; i<k; ++i){
		if(p<x[i]){
			break;
		}
		add_mod(memo[p],solve(p-x[i]));
	}
	return memo[p];
}

int main(void){
	int n,i;
	cin >> n >> k;
	for(i=0; i<k; ++i){
		cin >> x[i];
	}
	cout << solve(n) << endl;
	return 0;
}