#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;
using ll=long long;
int main(){
    string s;
    getline(cin,s);
    string ans="Yes";
    rep(i,s.length()){
        if(i%2==0){
            if(s[i]==' ')ans="No";
        }
        else{
            if(s[i]!=' ')ans="No";
        }
    }
    cout<<ans<<endl;
}