#define _USE_MATH_DEFINES #include "bits/stdc++.h" using namespace std; #define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i)) #define rep(i,j) FOR(i,0,j) #define each(x,y) for(auto &(x):(y)) #define mp make_pair #define MT make_tuple #define all(x) (x).begin(),(x).end() #define debug(x) cout<<#x<<": "<<(x)<; using vi = vector; using vll = vector; void solve() { int N; cin >> N; vll A(N + 1); rep(i, N) { cin >> A[i + 1]; if (A[i + 1] > i + 1) { cout << "No" << endl; return; } } ll S = 0; for (int i = N; i >= 1; --i) { if ((A[i] + S) % i) { cout << "No" << endl; return; } S += (A[i] + S) / i; } cout << "Yes" << endl; } int main() { ios::sync_with_stdio(false); cin.tie(0); cout << fixed << setprecision(15); solve(); return 0; }