#include <algorithm>
#include <bitset>
#include <cassert>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstring>
#include <deque>
#include <functional>
#include <iostream>
#include <iomanip>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include <cstdint>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
#define MP make_pair
#define PB push_back
#define inf 1000000007
#define rep(i,n) for(int i = 0; i < (int)(n); ++i)
#define all(x) (x).begin(),(x).end()

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
    std::fill( (T*)array, (T*)(array+N), val );
}
 
template<class T> inline bool chmax(T &a, T b){
    if(a<b){
        a = b;
        return true;
    }
    return false;
}

template<class T> inline bool chmin(T &a, T b){
    if(a>b){
        a = b;
        return true;
    }
    return false;
}


template <unsigned int mod>
class ModInt {
private:
    unsigned int v;
    static unsigned int norm(const unsigned int& x){ return x < mod ? x : x - mod; }
    static ModInt make(const unsigned int& x){ ModInt m; return m.v = x, m; }
    static ModInt inv(const ModInt& x){ return make(inverse(x.v, mod)); }
    static unsigned int inverse(int a, int m){
        int u[] = {a, 1, 0}, v[] = {m, 0, 1}, t;
        while(*v){
            t = *u / *v;
            swap(u[0] -= t * v[0], v[0]), swap(u[1] -= t * v[1], v[1]), swap(u[2] -= t * v[2], v[2]);
        }
        return (u[1] % m + m) % m;
    }

public:
    ModInt() : v{0}{}
    ModInt(const long long val) : v{norm(val % mod + mod)} {}
    ModInt(const ModInt<mod>& n) : v{n()} {}
    explicit operator bool() const noexcept { return v != 0; }
    bool operator!() const noexcept { return !static_cast<bool>(*this); }
    ModInt& operator=(const ModInt& n){ return v = n(), (*this); }
    ModInt& operator=(const long long val){ return v = norm(val % mod + mod), (*this); }
    ModInt operator+() const { return *this; }
    ModInt operator-() const { return v == 0 ? make(0) : make(mod - v); }
    ModInt operator+(const ModInt& val) const { return make(norm(v + val())); }
    ModInt operator-(const ModInt& val) const { return make(norm(v + mod - val())); }
    ModInt operator*(const ModInt& val) const { return make((long long)v * val() % mod); }
    ModInt operator/(const ModInt& val) const { return *this * inv(val); }
    ModInt& operator+=(const ModInt& val){ return *this = *this + val; }
    ModInt& operator-=(const ModInt& val){ return *this = *this - val; }
    ModInt& operator*=(const ModInt& val){ return *this = *this * val; }
    ModInt& operator/=(const ModInt& val){ return *this = *this / val; }
    ModInt operator+(const long long val) const { return ModInt{v + val}; }
    ModInt operator-(const long long val) const { return ModInt{v - val}; }
    ModInt operator*(const long long val) const { return ModInt{(long long)v * (val % mod)}; }
    ModInt operator/(const long long val) const { return ModInt{(long long)v * inv(val)}; }
    ModInt& operator+=(const long long val){ return *this = *this + val; }
    ModInt& operator-=(const long long val){ return *this = *this - val; }
    ModInt& operator*=(const long long val){ return *this = *this * val; }
    ModInt& operator/=(const long long val){ return *this = *this / val; }
    bool operator==(const ModInt& val) const { return v == val.v; }
    bool operator!=(const ModInt& val) const { return !(*this == val); }
    bool operator==(const long long val) const { return v == norm(val % mod + mod); }
    bool operator!=(const long long val) const { return !(*this == val); }
    unsigned int operator()() const { return v; }
    friend ModInt operator+(const long long val, const ModInt& n) { return n + val; }
    friend ModInt operator-(const long long val, const ModInt& n) { return ModInt{val - n()}; }
    friend ModInt operator*(const long long val, const ModInt& n) { return n * val; }
    friend ModInt operator/(const long long val, const ModInt& n) { return ModInt{val} / n; }
    friend bool operator==(const long long val, const ModInt& n) { return n == val; }
    friend bool operator!=(const long long val, const ModInt& n) { return !(val == n); }
    friend istream& operator>>(istream& is, ModInt& n){
        unsigned int v;
        return is >> v, n = v, is;
    }
    friend ostream& operator<<(ostream& os, const ModInt& n){ return (os << n()); }
    friend ModInt mod_pow(ModInt x, long long n){
        ModInt ans = 1;
        while(n){
            if(n & 1) ans *= x;
            x *= x, n >>= 1;
        }
        return ans;
    }
};

#define MOD 1000000007
using mod = ModInt<MOD>;


mod A[3][3]={{4,-2,1},{1,0,0},{0,1,0}};

vector<vector<mod> > calc(int n){
    vector<vector<mod> > res(3,vector<mod>(3));
    if(n==0){
        res[0][0] = 1;
        res[1][1] = 1;
        res[2][2] = 1;
        return res;
    }else if(n==1){
        rep(i,3)rep(j,3)res[i][j] = A[i][j];
        return res;  
    }else if(n%2==0){
        vector<vector<mod> > p;
        p = calc(n/2);
        rep(i,3)rep(j,3)rep(k,3)res[i][j] += p[i][k]*p[k][j];
        return res;
    }else{
        vector<vector<mod> > p;
        vector<vector<mod> > q(3,vector<mod>(3));
        p = calc(n/2);
        rep(i,3)rep(j,3)rep(k,3)q[i][j] += p[i][k]*p[k][j];
        rep(i,3)rep(j,3)rep(k,3)res[i][j] += q[i][k]*A[k][j];
        return res;
    }
}

int main(){
    int n,m;
    cin >> n >> m;
    vector<int>a(m);
    set<int> st;
    rep(i,m){
        cin >> a[i];
        st.insert(a[i]);
    }
    
    vector<mod> p(3);
    p[0] = 5;
    p[1] = 1;
    p[2] = 0;
    if(m!=0){
        if(a[0]==1){
            p[0] = 4;
        }
        int id = 2;
        int aid = 0;
        while(aid!=m&&id<n){
            if(st.count(id-1)==1||st.count(id)==1){
                mod nxt = p[0]*4-p[1]*2+p[2];
                if(st.count(id-1)==1){
                    nxt -= p[1];
                }
                if(st.count(id)==1){
                    nxt -= p[0];
                }
                id++;
                p[2] = p[1];
                p[1] = p[0];
                p[0] = nxt;
                continue;
            }
            if(id>=a[aid]){
                aid++;
                continue;
            }
            auto ss = calc(a[aid]-id);
            vector<mod> q(3);
            rep(i,3){
                rep(j,3){
                    q[i] += ss[i][j]*p[j];
                }
            }
            p = q;
            id = a[aid];
        }
        // cerr << id << " " << m << endl;
        if(id==n){
            cout << p[0] << endl;
        }else{
            auto ss = calc(n-id);
            vector<mod> q(3);
            rep(i,3){
                rep(j,3){
                    q[i] += ss[i][j]*p[j];
                }
            }
            p = q;
            cout << p[0] << endl;
        }
        // cerr << p[0] << " " << p[1] << " " << p[2] << endl;
    }else{
        if(n==1){
            cout << 1 << endl;
        }else{
            vector<vector<mod> > res = calc(n-2);
            mod ans = 0;
            rep(i,3){
                ans += res[0][i] * p[i];
            }
            cout << ans << endl;
        }
    }
    
    return 0;
}

Measured memory_bytes: 5376