#include <bits/stdc++.h>
using namespace std;
using ll = long long;
//const ll MOD = 1e9 + 7;
//const ll MOD = 998244353;
//const ll MOD = ;
ll mod(ll A, ll M) {return (A % M + M) % M;}
const ll INF = 1LL << 60;
template<class T> bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template<class T> bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
ll divceil(ll A, ll B) {return (A + (B - 1)) / B;}
ll myctoi(char C) {return C - '0';}
char myitoc(ll N) {return '0' + N;}
#define FINALANS(A) {cout << (A) << '\n'; exit(0);}

int main()
{
  string S;
  getline(cin, S);
  for (ll i = 0; i < S.size(); i++)
  {
    if (i % 2 == 0 && S.at(i) == ' ')
      FINALANS("No");
    if (i % 2 == 1 && S.at(i) != ' ')
      FINALANS("No");
  }
  FINALANS("Yes");
}