B.cpp

/*
 © 2021-02-20 06:01:23 Franco1010 All Rights Reserved
*/

// #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
// #pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
#define f first
#define s second
#define fore(i,a,b) for(int i = (a), ThxMK = (b); i < ThxMK; ++i)
#define pb push_back
#define all(s) begin(s), end(s)
#define _ ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define sz(s) int(s.size())
#define ENDL '\n'
using namespace std;
typedef long double ld;
typedef long long lli;
typedef pair<lli,lli> ii;
typedef vector<lli> vi;
#define deb(x) cout << #x": " << (x) << endl;

int main(){ _
  // freopen("file.in","r",stdin);
  // freopen("file.out","w",stdout);
  string s; cin >> s;
  bool yes = true;
  fore(i, 0, sz(s)){
    if(i&1){
      if('a' <= s[i] and s[i] <= 'z') yes = false;
    }else{
      if('A' <= s[i] and s[i] <= 'Z') yes = false;
    }
  }
  if(yes) cout << "Yes" << ENDL;
  else cout << "No" << ENDL;
  return 0;
}