#include <iostream> #include <algorithm> #include <vector> #include <string> #include <utility> #include <set> #include <map> #include <cmath> #include <queue> #include <cstdio> #include <limits> #define rep(i,n) for(int i = 0; i < n; ++i) #define rep1(i,n) for(int i = 1; i <= n; ++i) using namespace std; template<class T>bool chmax(T &a, const T &b) { if(a < b){ a = b; return 1; } return 0; } template<class T>bool chmin(T &a, const T &b) { if(a > b){ a = b; return 1; } return 0; } template<class T> inline int sz(T &a) { return a.size(); } using ll = long long; using ld = long double; using pi = pair<int,int>; using pl = pair<ll,ll>; using vi = vector<int>; using vvi = vector<vi>; using vl = vector<ll>; using vvl = vector<vl>; const int inf = numeric_limits<int>::max(); const ll infll = numeric_limits<ll>::max(); int main() { ll n,k; cin >> n >> k; vl a(k); rep(i,k) cin >> a[i]; rep(i,k) { rep(j,k) { if(i >= j) continue; if(a[i] + 1 == a[j]) { if(a[i] - 1 == 1 || a[i] - 2 == 1 || a[i] - 4 == 1 || a[i] - 7 == 1) { } else { cout << "No" << "\n"; return 0; } } if(a[i] + 3 == a[j]) { if(a[i] - 1 == 1 || a[i] - 4 == 1) { } else { cout << "No" << "\n"; return 0; } } if(a[i] + 5 == a[j]) { if(a[i] - 2 == 1 || a[i] - 3 == 1 || a[i] - 5 == 1 || a[i] - 8 == 1) { } else { cout << "No" << "\n"; return 0; } } } } cout << "Yes" << "\n"; return 0; }