#include"bits/stdc++.h"
#define rep(i,n) for(ll i=0;i<n;++i)
#define ALL(x) x.begin(),x.end()
#define BACK(x) x.rbegin(),x.rend()
#define MOD 1000000007
#define INF INT_MAX
#define FLOAT_ANS setprecision(30)
#define elif else if

using namespace std;
typedef long long ll;
typedef unsigned long long ull;

int main(void){
	string s;
	cin>>s;
	rep(i,s.length()){
		if(i%2){
			if(s[i]>'Z'){
				cout<<"No";
				return 0;
			}
		}
		else{
			if(s[i]<'a'){
				cout<<"No";
				return 0;
			}
		}
	}
	cout<<"Yes";
}


/*

*/


#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <functional>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <bitset>
#include <math.h>
#include <random>
#include <chrono>
#include <assert.h>
#include <climits>

using namespace std;
#define int long long

signed main() {
  int n;
  cin >> n;

  int sum = 0;
  for (int i = 1;; i++) {
    sum += i;
    if (sum >= n) {
      cout << i << '\n';
      return 0;
    }
  }
}