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89#include <bits/stdc++.h>
#include <cstdio>

using ll = long long;
using namespace std;
int main() {
    ll N, M; cin >> N >> M;

    vector<ll> a(M);
    for(ll i=0;i<M;++i)cin>>a[i];

    ll num[100100] = {};
    ll brokenis1[100100] = {};
    for(ll i=0; i<M; ++i) brokenis1[a[i]] = 1;
    num[0] = 1;
    num[1] = 0;
    for (ll i = 2; i <= N; i++) {
        if(brokenis1[i] == 0) {
            num[i] = (num[i-1] + num[i-2]) % 1000000007;
        }
    }
    cout << num[N] << "\n";
}