#include <bits/stdc++.h>
using namespace std;
using lint         = long long;
constexpr lint inf = 1LL << 60;
constexpr lint mod = 1000000007;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    lint n, k;
    cin >> n >> k;
    vector<lint> a(k);
    priority_queue<lint> pq;
    for (int i = 0; i < k; ++i) {
        cin >> a[i];
        pq.push(a[i]);
    }
    map<lint, bool> mp;
    while (!pq.empty()) {
        lint idx = pq.top();
        pq.pop();
        if (idx <= 0)
            break;
        mp[idx] = true;
        bool ok = false;
        for (lint j = idx + 1; j <= idx + 6; ++j) {
            if (!mp[j])
                ok = true;
        }
        if (!ok) {
            cout << "No"
                 << "\n";
            return 0;
        }
        if (mp[idx + 5]) {
            pq.push(idx - 1);
        }
        if (mp[idx + 3]) {
            pq.push(idx - 2);
        }
        if (mp[idx + 1]) {
            pq.push(idx - 3);
        }
    }
    if (mp[1]) {
        cout << "No"
             << "\n";
    } else {
        cout << "Yes"
             << "\n";
    }
    return 0;
}