#include<bits/stdc++.h>
using namespace std;
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(c) (c).begin(),(c).end()
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll inf=1e9+7;
int main(){
    string s;
    cin>>s;
    bool f=1;
    rep(i,s.size()){
        if(i%2==0){
            if(s[i]-'a'>=0&&s[i]-'a'<26);
            else f=0;
        }else{
            if(s[i]==' ');
            else f=0;
        }
    }
    cout<<(f?"Yes":"No")<<endl;
}