#define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include typedef long long int ll; //#include using namespace std; ll gcd(ll a, ll b) { if (a < b)swap(a, b); if (b == 0)return a; return gcd(b, a % b); } int lcm(int a, int b) { return a * b / gcd(a, b); } int main() { int Q; Q = 1; //cin >> Q; while (Q--) { ll n; cin >> n; ll r = n; n /= 3; for (int i = n - 2; i < n + 5; i++) { ll p = 0; for (int j = i; j < i + 3; j++) { p += j; } if (r == p) { cout << "YES"; return 0; } } cout << "NO"; } return 0; }