#include<bits/stdc++.h>
using namespace std;

string S;
int main(){
  cin >> S;
  int ans = 0;
  for(int i=0; i<S.size(); i++){
    if(i%2==0){
      //奇数番目
      if(isupper(S[i])){
        ans += 1;
      }
    }
        //大文字の時
    else{
      if(islower(S[i])){
              //偶数番目
        ans += 1;
      }
    }
  }
  if(ans == 0){
    cout << "Yes" << endl;
  }
  else{
    cout << "No" << endl;
  }
}
#include <bits/stdc++.h>
using namespace std;
#define lli long long int 
#define MOD 1000000007
#define fi(i,a,n) for(lli i = a; i < n; i++)
#define fd(i,a,n) for(lli i = a; i > n; i--)
#define fv(i,a) for(auto i:a)
#define pb push_back
#define mp make_pair


int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout<<fixed<<setprecision(10);

// #ifndef ONLINE_JUDGE
//     freopen("input.txt", "r", stdin);
//     freopen("output.txt", "w", stdout);
// #endif
lli t=1;
//cin>>t;
while(t--)
{
	string s;
	cin>>s;
	fi(i,0,s.size()){
		if(i%2==0 && isupper(s[i])) {
			cout<<"No";
			return 0;
		} 
		if(i%2==1 && islower(s[i])) {
			cout<<"No";
			return 0;
		}
	}
	cout<<"Yes";
}
return 0;
}