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

void solve(int i, string &s) {
  if (i == s.size()) {
    cout << "Yes";
    return;
  }

  if ((i + 1) % 2 == 0) {
    if (s[i] == tolower(s[i])) {
      cout << "No";
      return;
    } else {
      solve(i + 1, s);
    }
  } else {
    if (s[i] == toupper(s[i])) {
      cout << "No";
      return;
    } else {
      solve(i + 1, s);
    }
  }
}

int main() {
  string s;
  cin >> s;
  if (s.size() == 1) {
    if (s[0] == toupper(s[0])) {
      cout << "No";
    } else {
      cout << "Yes";
    }
  } else {
    solve(0, s);
  }
  return 0;
}