#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;
  cin >> s;
  bool ok = true;
  rep(i,sz(s)) {
    if (i%2 == 0 && (s[i] == ' ')) ok = false;
    if (i%2 != 0 && s[i] != ' ') ok = false;
  }
  if (ok) puts("Yes");
  else puts("No");
  return 0;
}