#include using namespace std; #include using namespace atcoder; #define rep(i, n) for(int i=0;i<(n);++i) #define rep1(i, n) for(int i=1;i<=(n);i++) #define ll long long using mint = modint998244353; using P = pair; using lb = long double; using T = tuple; #ifdef LOCAL # include # define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__) #else # define dbg(...) (static_cast(0)) #endif int main() { int n; cin >> n; vector a(1<> a[i]; if(a[0]!=0){ cout << "No" << endl; } else{ cout << "Yes" << endl; } return 0; }