#include <bits/stdc++.h>
using namespace std;
int main(){
  string S;
  cin >> S;
  int ans = 0;
  for(int i = 0; i < S.size(); i++){
    if(i % 2 == 0 && S.at(i) > 'Z') ans++;
    if(i % 2 == 1 && S.at(i) < 'a') ans++;
  }
  if(ans == S.size()) cout << "Yes" << endl;
  else cout << "No" << endl;
  return 0;
}
#include<bits/stdc++.h>
using namespace std;

// #pragma GCC target ("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimization ("unroll-loops")
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #pragma GCC target("fpmath=387") //extra precision    

#define debug_input cout<<"input"<<endl;freopen("input.txt","r",stdin);
#define debug_output cout<<"output"<<endl;freopen("output.txt","w",stdout);
#define debug debug_input;debug_output;

typedef double db;
typedef string str;
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;

typedef pair<int,int> pi;
typedef pair<ll,ll> pl;
typedef pair<double,double> pd;

#define F first
#define S second
#define endl '\n'
#define ALL(a) a.begin(),a.end()
#define mp make_pair
#define pb push_back
#define FOR(i,a,b) for(int i=a;i<(int)b;i++)
#define FORN(i,a,b) for(int i=a;i<=(int)b;i++)
#define FORB(i,a,b) for(int i=a;i>=(int)b;i--)
#define REP(i,x) FOR(i,0,x)
#define MEM(arr, x) memset(arr, (x), sizeof(arr))

typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<str> vs;
typedef vector<pi> vii;
typedef vector<pl> vll;

const int MOD = 1e9+7; 
const ll INF = 1e18;
const ld PI = acos((ld)-1);

const int d4i[4]={-1, 0, 1, 0}, d4j[4]={0, 1, 0, -1};
const int d8i[8]={-1, -1, 0, 1, 1, 1, 0, -1}, d8j[8]={0, 1, 1, 1, 0, -1, -1, -1};

void solve(){
    str x;
    cin>>x;

    int a = 1, b = 1;
    for(int i=0;i<(int)x.size();i+=2)
        if(x[i] >= 'A' && x[i] <= 'Z')
            a = 0;
    for(int i=1;i<(int)x.size();i+=2)
        if(x[i] >= 'a' && x[i] <= 'z')
            b = 0;
    if(a && b)  cout<<"Yes";
    else    cout<<"No";
    cout<<endl;
}
int main(){
    ios_base::sync_with_stdio(false);cin.tie(nullptr);
    // cout.tie(nullptr);
    // debug_output;
    // debug;
    
    int t = 1;
    // cin>>t;
    for(int tc=1;tc<=t;tc++){
        // cout<<"Case #"<<tc<<": ";
        solve();
    }
    return 0;
}