#include #include #include #include #include #include #include using namespace std; typedef long long int ll; typedef pair Pii; const ll mod = 1000000007; int main() { cin.tie(0); ios::sync_with_stdio(false); string s; cin >> s; for (int i = 0; i < s.length(); i += 2) { if (s[i] < 'a' || s[i] > 'z') { cout << "No" << endl; return 0; } } for (int i = 1; i < s.length(); i += 2) { if (s[i] != ' ') { cout << "No" << endl; return 0; } } cout << "Yes" << endl; return 0; }