#include "bits/stdc++.h"
using namespace std;
//#include "testlib.h"
#define ff first
#define ss second
#define all(v) v.begin(),v.end()
#define int long long
#define ll long long
#define M 1000000007
#define MM 998244353
#define inputarr(a,n) for(int i=0;i<n;++i) cin>>a[i]
#define GCD(m,n) __gcd(m,n)
#define LCM(m,n) m*(n/GCD(m,n))
#define mii  map<ll ,ll >
#define msi  map<string,ll >
#define rep(a,b)    for(ll i=a;i<b;i++)
#define rep0(n)    for(ll i=0;i<n;i++)
#define repi(i,a,b) for(ll i=a;i<b;i++)
#define pb push_back
#define vi vector<ll>
#define vs vector<string>
#define ppb pop_back
#define endl '\n'
#define asdf ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define r0 return 0;
#define FORD(i, a, b) for (int i = (int) (a); i >= (int) (b); --i)
#define inputoutput freopen("input.txt", "r", stdin);freopen("output.txt", "w", stdout);
#define Set(a, s) (a, s, sizeof (a))
#define FOR repi
#define vii vector<pii>
#define pii pair<int,int>
#define REVERSE(v) reverse(all(v))
#define trav(a, x) for(auto& a : x)
#define display(x) trav(a,x) cout<<a<<" ";cout<<endl
#define debug cerr<<"bhau"<<endl
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
    std::cerr << name << " : " << arg1 << endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
    const char* comma = strchr(names + 1, ',');std::cerr.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);
}
template<typename T, typename U> static inline void amin(T &x, U y) 
{ 
    if (y < x) 
        x = y; 
}
template<typename T, typename U> static inline void amax(T &x, U y) 
{ 
    if (x < y) 
        x = y; 
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};



ll max(ll a, ll b) { return (a > b)? a : b;}
int min(int a, int b) { return (a < b)? a : b;} 


int solve(){

    string s;
    cin>>s;

    for(int i=0;i<s.size();i++){
        if(i%2==0){
            if(s[i]>'z' || s[i]<'a')
                return cout<<"No"<<endl,0;
        }
        else {
            // if(s[i]>)
             if(s[i]>'Z' || s[i]<'A')
                return cout<<"No"<<endl,0;
        }
    }
    cout<<"Yes";

    return 0;
}
signed main(){
    asdf
    int t=1;
    // cin>>t;
    while(t--){
        solve();
    }
    return 0;
}

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

//#define int		long long
#define pb		push_back
#define ppb		pop_back
#define pf		push_front
#define ppf		pop_front
#define all(x)		(x).begin(),(x).end()
#define uniq(v)		(v).erase(unique(all(v)),(v).end())
#define sz(x)		(int)((x).size())
#define fr		first
#define sc		second
#define pii		pair<int,int>
#define rep(i,a,b)	for(int i=a;i<b;i++)
#define mem1(a)		memset(a,-1,sizeof(a))
#define mem0(a)		memset(a,0,sizeof(a))
#define ppc		__builtin_popcount
#define ppcll		__builtin_popcountll
//#define rep(i, n) for (int i = 0; i < (int)(n); i++)

//template<typename T1,typename T2>istream& opertor>>(istream& in,pair<T1,T2> &a){in>>a.fr>>
//template<typename T1,typename T2>istream& opertor<<(ostream& out,pair<T1,T2> a){out<<a.fr<<
template<typename T,typename T1>T amax(T &a,T1 b){if(b>a)a=b;return a;}
template<typename T,typename T1>T amin(T &a,T1 b){if(b<a)a=b;return a;}

const long long INF=1e18;
const int32_t M=1e9+7;
const int32_t MM=998244353;

int main() {
  string S;
  cin >> S;
  
  string ans = "Yes";
  
  rep(i,0,S.size()){
    if(i%2==0){
      if(isupper(S.at(i))){
      	ans = "No";
        break;
      }
    }else if((i%2==1)){
      if(islower(S.at(i))){
      	ans = "No";
        break;
      }
    }
  }
  
  cout << ans << endl;
  
  }