#include #include #include using namespace std; using ll = long long; using ull = unsigned long long; int main(){ ull n; int k; cin >> n >> k; vector a(k + 1 , 0); for(int i = 1; i <= k; i++){ cin >> a[i]; a[i] += 10; } ull mx =*max_element(a.begin() , a.end()); vector check(mx + 50 , 0); for(int i = 1; i <= k; i++){ check[a[i]] = 1; } for(ull i = mx; i >= 10; i--){ if(check[a[i] + 5] == 1)check[a[i] - 1] = 1; if(check[a[i] + 3] == 1)check[a[i] + 4] = 1; if(check[a[i] + 1] == 1)check[a[i] - 3] = 1; } if(check[11] == 1)cout << "No" << endl; else cout << "Yes" << endl; return 0; }