#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
int main()
{
    string s;
    cin>>s;
    ll flag=0;
    for(int i=0;i<s.size();i++)
    {
        if(i%2==0)
        {
            if((s[i]>='A'&&s[i]<='Z'))
            {
                
                flag=1;
                break;
            }
        }
        else
        {
            if((s[i]>='a'&&s[i]<='z'))
            {
                
                flag=1;
               break;
            }
            
        }
    }
    if(flag)
    {
        cout<<"No";
    }
    else cout<<"Yes";
}
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define loop(p,n) for(int i=p;i<n;i++)
#define test() int t;cin>>t;while(t-->0) 
#define speed ios_base::sync_with_stdio(false);   cin.tie(NULL);   cout.tie(NULL);
#define endl "\n" 
#define mp make_pair
#define pb push_back
#define mod 1000000007


int main()
{

    string s;
    cin>>s;
   bool ans=true;
    for(int i=0;i<s.size();i++)
    {
        if(i%2==0)
        {
            if(s[i]>='A'&&s[i]<='Z')
            ans=false;
        }
        else
        {
             if(s[i]>='a'&&s[i]<='z')
            ans=false;
        }
        
    }

    if(ans)
    cout<<"Yes"<<endl;
    else
    cout<<"No"<<endl;
    

}
