#pragma GCC target ("avx2")
//#pragma GCC optimize "trapv"
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#include <bits/stdc++.h>
#define input(a,n) for(ll i1=0;i1<n;i1++)cin>>a[i1]
#define ll long long
#define pi 2 * acos(0.0)
#define usll unordered_set<ll>
#define sll set<ll>
#define vll vector<ll>
#define mll map<ll,ll>
#define pll pair<ll,ll>
#define umll unordered_map<ll,ll>
#define S second
#define sz size()
#define all(v) v.begin(),v.end()
#define Y cout<< "Yes"<< "\n"
#define N cout<< "No"<< "\n"
#define F first
#define mp make_pair
#define pb push_back
#define pf push_front
#define ld long double
using namespace std;
const ll mod = 1000000007;
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    #ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif
    string s;
    cin>>s;
    ll n=s.sz,f=1,g=1;
    for(ll i=0;i<n;i+=2)
    {
      if((ll)s[i]<97)
      {
        f=0;
        break;
      }
    }
    for(ll i=1;i<n;i+=2)
    {
      if((ll)s[i]>=97)
      {
        g=0;
        break;
      }
    }
    if(f&&g)
      Y;
    else
      N;
    return 0;
}
/*
 * Created by : imay_10 (Ayush Mishra)
 * 
 * " It won't happen, until you make it happen !!! "
 * 
 * Template for CP contests
 */
 
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const ll mxn = 1e6;
const int mod1 = 1e9+7;
const int mod2 = 998244353;
const ll inf = 1e18;
const double pi = 3.1415926535897932384626;

// Utility for fast exponentiation
ll binpow(ll a, ll b){
	ll res = 1;
    while (b > 0) {
        if (b & 1)
            res = res * a;
        a = a * a;
        b >>= 1;
    }
    return res;
} 

// Utility for modular exponentiation
ll mpow(ll a, ll b, ll m) {
    a %= m;
    ll res = 1;
    while (b > 0) {
        if (b & 1)
            res = res * a % m;
        a = a * a % m;
        b >>= 1;
    }
    return res;
}

// Utility for modular inverse
ll inv(ll a, ll m){
	return mpow(a, m-2, m);
}

// Utility for GCD of two numbers
ll gcd(ll a, ll b){
	if (b == 0)
        return a;
    else
        return gcd (b, a % b);
}

// Utility for LCM of two numbers
ll lcm(ll a, ll b){
	return a / gcd(a, b) * b;
}

// Utility for binomial coefficient
ll ncr(ll n, ll k)
{
    if(n < k)
        return 0;
    ll C[n + 1][k + 1];
    ll i, j;
    for(i = 0; i <= n; i++){
        for(j = 0; j <= min(i, k); j++){
            if (j == 0 || j == i)
                C[i][j] = 1;
            else
                C[i][j] = (C[i-1][j-1] + C[i-1][j]);
        }
    }
    return C[n][k];
}

class Solution{
    public :
    void solve(){
        // Write your code here
        string s;
        cin>>s;
        ll n=s.length();
        int f=0;
        
        for(ll i=0;i<n;i++){
			if(i%2==0 and s[i]>=97 and s[i]<=122)
				f=0;
			else if(i%2==1 and s[i]>=65 and s[i]<=90)
				f=0;
			else{
				f=1;
				break;
			}
		}
		if(f==1) cout<<"No";
		else cout<<"Yes";	
    }
};

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    
    clock_t start, end;
    start = clock();
    Solution ob;  


    /*
	#ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
    */ 
    
    // Call the solve() function here
    ob.solve();
    
    // Call the solve() function with multiple test_cases
    /*
    int t;
    cin>>t;
    for(int i=1;i<=t;i++){
		ob.solve();
		cout<<"\n";
	}
	*/
	
	end = clock();
	
	double time_taken=double(end-start)/double(CLOCKS_PER_SEC);
    cerr<<"\nTime : "<<fixed<<time_taken<<setprecision(5)<<" s \n";
    
    return 0;
}
