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

int main(){
  string s;
  int n;
  cin >> s;
  n = s.size();
  
  for (int i = 0; i < n ; i++){
    if (i%2 == 0){
      if (s.at(i) == 'A' || s.at(i) == 'B' || s.at(i) == 'C' || s.at(i) == 'D' || s.at(i) == 'E' || s.at(i) == 'F' || s.at(i) == 'G' || s.at(i) == 'H' || s.at(i) == 'I' || s.at(i) == 'J' || s.at(i) == 'K' || s.at(i) ==
 'L' || s.at(i) == 'M' || s.at(i) == 'N' || s.at(i) == 'O' || s.at(i) == 'P' || s.at(i) == 'Q' || s.at(i) == 'R' || s.at(i) == 'S' || s.at(i) == 'T' || s.at(i) == 'U' || s.at(i) == 'V' || s.at(i) == 'W' || s.at(i) == 'X' || s.at(i) == 'Y' || s.at(i) == 'Z'){
        cout << "No" << endl;
        break;
        }
    }
    if (i%2 == 1){
      if (s.at(i) == 'a' || s.at(i) == 'b' || s.at(i) == 'c' || s.at(i) == 'd' || s.at(i) == 'e' || s.at(i) == 'f' || s.at(i) == 'g' || s.at(i) == 'h' || s.at(i) == 'i' || s.at(i) == 'j' || s.at(i) == 'k' || s.at(i) ==
 'l' || s.at(i) == 'm' || s.at(i) == 'n' || s.at(i) == 'o' || s.at(i) == 'p' || s.at(i) == 'q' || s.at(i) == 'r' || s.at(i) == 's' || s.at(i) == 't' || s.at(i) == 'u' || s.at(i) == 'v' || s.at(i) == 'w' || s.at(i) == 'x' || s.at(i) == 'y' || s.at(i) == 'z'){
        cout << "No" << endl;
        break;
        }
    }
    if (i == n-1){
      cout << "Yes" << endl;
    }
  }
}
#include <bits/stdc++.h>

using namespace std;

#define rep(i,n)      for(long long(i)=0;(i)<(n);(i)++)
#define kiriage(a,b)  ((a)+(b)-1)/(b)

int main(){

    string s;
    cin >> s;

    rep(i,s.length()){
        if(i & 0x01){
            if(s[i] < 'A' || 'Z' < s[i]){
                cout << "No" << endl;
                return 0;
            }
        } else {
            if(s[i] < 'a' || 'z' < s[i]){
                cout << "No" << endl;
                return 0;
            }
        }
    }

    cout << "Yes" << endl;

    return 0;
}
