#include<bits/stdc++.h>
using namespace std;
typedef long long ll;



signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(20);
 
    string s;
    getline(cin,s);
    int n = s.size();
    bool pos = true;
    for(int i=0;i<n;i++){
        if(i%2 && s[i]!=' ') pos = false;
        if(i%2==0 && s[i]==' ') pos = false;
    }
    if(pos){
        cout <<"Yes\n";
    }
    else cout <<"No\n";

    
}