///スマホコーディング
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<int(n);++i)
typedef long long ll;
const int inf=1e9;
int main(){
  string s;cin>>s;
  rep(i,s.size()){
    if((i%2==0&&!islower(s[i]))||
       (i%2==1&&s[i]!=' ')){
      cout<<"No"<<endl;
      return 0;
    }
  }
  cout<<"Yes"<<endl;
  return 0;
}