#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(LL i = a;i<b; i++)
#define rrep(i,a,b) for(LL i = a;i>=b; i--)
#define INF ((1LL<<62)-(1LL<<31))
#define ooki 9,223,372,036,854,775,807
#define tii -9,223,372,036,854,775,808
typedef long long LL;
int main(){
  string s;
  cin >> s;
  getline(cin,s);
  rep(i,0,s.size()){
    if(i%2==1&&s[i]==' '){cout<<"No";return 0;}
    if(i%2==0&&s[i]!=' '){cout<<"No";return 0;}
    
  }
  cout<<"Yes"<<endl;
}