#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); ++i)
using ll = long long;

int main(){
    string s; cin >> s;
    if(s.size()%2==0){
        cout << "No" << endl;
        return 0;
    }

    rep(i,s.size()){
        if(i%2==0){
            if(!('a'<=s[i] && s[i]<='z')){
                cout << "No" << endl;
                return 0;
            }
        }else{
            if(s[i]!=' '){
                cout << "No" << endl;
                return 0;
            }
        }
    }
    cout << "Yes" << endl;
}