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

int main(){
    string s;
    getline(cin,s);
    for(int i=0;i<s.size();i++){
        if(i%2==0&&s[i]==' '){
            cout << "No" << endl;
            return 0;
        }   
    }
    for(int i=0;i<s.size();i++){
        if(i%2==1&&s[i]!=' '){
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
    return 0;
}