#include #include // #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DEBUG(x) cout << #x << ": " << x << endl #define INFILE() freopen("input.txt", "r", stdin) #define REP(i, a, b) for (int i = (a); i < (b); i++) #define REPC(i, a) REP(i, 0, a) #define RREP(i, a, b) for (int i = (a); i >= (b); i--) #define RREPC(i, a) RREP(i, a, 0) #define ALL(s) begin(s), end(s) #define RALL(s) rbegin(s), rend(s) using namespace std; using ll = long long; using ull = unsigned long long; using i_i = pair; using ll_i = pair; using i_ll = pair; using d_i = pair; using ll_ll = pair; using d_d = pair; static constexpr ll LL_MOD = 1000000009; static constexpr ll LL2_MOD = 1000000007; static constexpr double EPS = numeric_limits::epsilon(); static constexpr double PI = 3.14159265358979323846264338327950288; static map scanType = { { typeid(int), "%d" }, { typeid(ll), "%lld" }, { typeid(double), "%lf" }, { typeid(char), "%c" }, {typeid(ull) , "%lld"} }; template static void scan(vector &v); static void scan(vector &v, bool isWord = true); // static boost::dynamic_bitset<> scan(char trueValue = 'o'); int main(int argc, char *argv[]) { // INFILE(); ll n, a; cin >> n >> a; vector v(n); scan(v); cout << (accumulate(ALL(v), 0) == a * v.size() ? "YES\n" : "NO\n"); return 0; } template static void scan(vector &v) { auto tFormat = scanType[typeid(T)]; for (T &n : v) { scanf(tFormat, &n); } } static void scan(vector &v, bool isWord) { if (isWord) { for (auto &n : v) { cin >> n; } return; } int i = 0, size = v.size(); string s; getline(cin, s); if (s.size() != 0) { i++; v[0] = s; } for (; i < size; ++i) { getline(cin, v[i]); } } //static boost::dynamic_bitset<> scan(char trueValue) { // string s; // getline(cin, s); // // if (s.size() == 0) { // getline(cin, s); // } // // for_each(begin(s), end(s), // [trueValue](char &c) { c = (c == trueValue) ? '1' : '0'; }); // return boost::dynamic_bitset<>(string(rbegin(s), rend(s))); //}