#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    #ifndef ONLINE_JUDGE
    // for getting input from input.txt
    freopen("input.txt", "r", stdin);
    // for writing output to output.txt
    freopen("output.txt", "w", stdout);
    #endif

    int N; cin >> N; N++;
    int M; cin >> M;
    bool valid[N]; F0R(i, N) valid[i] = true;
    F0R(i, M) {
        int cur; cin >> cur; valid[cur] = false;
    }

    ll dp[N]; dp[0] = 1; 
    if (valid[1]) {
        dp[1] = 1;
    } else dp[1] = 0;
    FOR(i, 2, N) {
        if (valid[i]) {
            dp[i] = dp[i-1] + dp[i-2];
            dp[i] = dp[i] % MOD;
        } else dp[i] = 0;
    }

    cout << dp[N-1] << endl;


    return 0;
}

// read the question correctly (ll vs int)
// template by bqi343