#include "bits/stdc++.h" using namespace std; signed main() { ios::sync_with_stdio(false); cin.tie(nullptr); string s; getline(cin, s); for (size_t i = 0; i < s.length(); i += 2) { if ('a' <= s[i] && s[i] <= 'z') { continue; } else { cout << "No" << "\n"; return 0; } } for (size_t i = 1; i < s.length(); i += 2) { if (s[i] != ' ') { cout << "No" << "\n"; } } cout << "Yes" << "\n"; return 0; }