#pragma GCC optimize "O3" #pragma GCC target "avx" #include #include #include #include #include #include #include #include #include #include #include #include #include #define repeat(i,n) for (int i = 0; (i) < int(n); ++(i)) #define whole(f,x,...) ([&](decltype((x)) whole) { return (f)(begin(whole), end(whole), ## __VA_ARGS__); })(x) using ll = long long; using namespace std; ll gcd(ll a, ll b) { while (a) { b %= a; swap(a, b); } return b; } struct rational_t { ll p, q; rational_t() : p(0), q(1) {} rational_t(ll num, ll den = 1) : p(num), q(p ? den : 1) {} rational_t(rational_t const & other) : p(other.p), q(other.q) {} rational_t & operator = (rational_t const & other) { this->p = other.p; this->q = other.q; return *this; } bool operator == (rational_t other) const { return this->p == other.p and this->q == other.q; } rational_t operator + (rational_t other) const { return { this->p * other.q + other.p * this->q, this->q * other.q }; } rational_t operator - (rational_t other) const { return { this->p * other.q - other.p * this->q, this->q * other.q }; } rational_t operator * (rational_t other) const { return { this->p * other.p, this->q * other.q }; } rational_t operator / (rational_t other) const { return { this->p * other.q, this->q * other.p }; } }; constexpr int max_n = 7; struct loop_exception {}; int main() { int n; scanf("%d", &n); vector a(n); repeat (i,n) scanf("%d", &a[i]); whole(sort, a); bool found = false; array x; repeat (i,n) x[i] = rational_t(a[i]); function go = [&](int n) { if (n <= 1) return; repeat (j,n) { swap(x[j], x[n-1]); repeat (i,j) { if (x[i] == x[n-1]) { throw loop_exception {}; } rational_t saved = x[i]; x[i] = saved + x[n-1]; go(n-1); x[i] = saved - x[n-1]; go(n-1); x[i] = saved * x[n-1]; go(n-1); if (x[n-1].p) { x[i] = saved / x[n-1]; go(n-1); } x[i] = saved; } swap(x[j], x[n-1]); } }; try { go(n); } catch (loop_exception e) { found = true; } printf("%s\n", found ? "YES" : "NO"); return 0; }