#include using namespace std; typedef long long ll; #define pa pair #define pal pair #define pali pair #define pad pair #define pb push_back #define mp make_pair #define COUT(v) \ for (int64_t i = 0; i < (v).size(); ++i) \ { \ cout << v.at(i) << endl; \ } #define REP(i, n) for (int64_t i = 0; i < n; ++i) #define FOR(i, r, n) for (int64_t i = (r); i < n; ++i) #define VIN(v) \ for (int64_t i = 0; i < (v).size(); ++i) \ { \ cin >> (v).at(i); \ } typedef vector bvec; typedef vector ivec; typedef vector lvec; typedef vector dvec; typedef vector pavec; typedef vector palivec; typedef vector palvec; typedef vector> bmat; typedef vector> imat; typedef vector> lmat; typedef vector svec; typedef vector> smat; const ll infll = (1LL << 60) - 1; const int inf = (1 << 30) - 1; const ll MOD = 1000000007; ll gcd(ll x, ll y) { ll r = x % y; if (r == 0) return y; else return gcd(y, r); } ll lcm(ll x, ll y) { return x * y / gcd(x, y); } lvec mfactor(ll n) { bvec ip(n, true); lvec mf(n, -1); ip[0] = false; ip[1] = false; mf[0] = 0; mf[1] = 1; REP(i, n) { if (ip[i]) { mf[i] = i; for (ll j = i * i; j < n; j += i) { ip[j] = false; if (mf[j] == -1) mf[j] = i; } } } return mf; } palivec get_prime(ll n, const lvec &mf) { palivec plist; while (n != 1) { int cnt = 0; ll m = mf[n]; while (mf[n] == m) { cnt++; n /= m; } plist.pb(pali(m, cnt)); } return plist; } void COMinit(int m, lvec &fac, lvec &finv) { lvec inv(m); fac[0] = fac[1] = 1; finv[0] = finv[1] = 1; inv[1] = 1; for (int i = 2; i < m; i++) { fac[i] = fac[i - 1] * i % MOD; inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD; finv[i] = finv[i - 1] * inv[i] % MOD; } } ll pow_mod(ll a, ll n) { ll x = 1; while (n > 0) { if (n & 1) { x = x * a % MOD; } a = a * a % MOD; n >>= 1; } return x; } ll pow_mod2(ll a, ll n) { ll x = 1; while (n > 0) { if (n & 1) { x = x * a; } a = a * a; n >>= 1; } return x; } ll COM(int n, int k, const lvec &fac, const lvec &finv) { if (n < k) return 0; if (n < 0 || k < 0) return 0; return (fac[n] * (finv[k] * finv[n - k] % MOD)) % MOD; } ll modinv(ll a, ll m) { ll b = m, u = 1, v = 0; while (b) { ll t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v); } u %= m; if (u < 0) u += m; return u; } // union by size + path having class UnionFind { public: vector par; vector siz; // Constructor UnionFind(ll sz_) : par(sz_), siz(sz_, 1LL) { for (ll i = 0; i < sz_; ++i) par[i] = i; } void init(ll sz_) { par.resize(sz_); siz.assign(sz_, 1LL); for (ll i = 0; i < sz_; ++i) par[i] = i; } // Member Function // Find ll root(ll x) { while (par[x] != x) { x = par[x] = par[par[x]]; } return x; } // Union(Unite, Merge) bool merge(ll x, ll y) { x = root(x); y = root(y); if (x == y) return false; if (siz[x] < siz[y]) swap(x, y); siz[x] += siz[y]; par[y] = x; return true; } bool issame(ll x, ll y) { return root(x) == root(y); } ll size(ll x) { return siz[root(x)]; } }; int main() { cin.tie(0); ios::sync_with_stdio(false); ll n; cin >> n; lvec a(n); for (int i = 0; i < n; i++) { cin >> a[i]; } ll s = 0; for (int i = n - 1; i >= 0; --i) { ll ss = s + a[i]; if (ss % (i + 1)) { cout << "No" << endl; return 0; } s += ss / (i + 1); } cout << "Yes" << endl; }