#include <bits/stdc++.h>
//#include <iostream>
#include <atcoder/all>
#include <math.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rrep(i, n) for(int i = (n-1); i >= 0; i--)
using namespace std;
using namespace atcoder;
typedef long long ll;
const int MOD = 1000000007;
//const int MOD =  998244353;
 
const ll INF = 1LL<<61;
const int IINF = 1000000000;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

typedef pair<int, int> PI;
typedef pair<ll, ll> P;
typedef pair<string, ll> PS;

using mint = modint1000000007;

#include <regex>
int main(){

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    string S; cin >> S;
    int n = S.size();

    bool isok = true;
    rep(i,n){
        if(i%2 == 0){
            if(!('a' <= S[i] && S[i] <= 'z'))isok = false;
        }
        else{
            if(!(S[i] == ' '))isok = false;
        }
    }
    if(isok) cout << "Yes" << endl;
    else cout << "No" << endl;

}