#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef pair<int,int> P;
using Graph = vector<vector<pair<int,P>>>; 
const int INF = 1e9;

int main(){
  string s;
  getline(cin,s);
  bool ok = true;
  rep(i,s.length()) {
    if (i%2 == 0) {
      if (s[i] == ' ') ok = false;
    }
    else {
      if (s[i] != ' ') ok = false;
    }
  }
  if (ok) puts("Yes");
  else puts("No");
  return 0;
}