#include<bits/stdc++.h>
using namespace std;
int main()
{
    char s[105];
    int a=0;
    cin.getline(s,105);
    if(s[0]<='z' and s[0]>='a'){
            cout<<"No";
            return 0;
        }
    for(int i=1;s[i]!='\0';i+=1){
        if(s[i]<='Z' and s[i]>='A'){
            cout<<"No";
            return 0;
        }
        
	}
	cout<<"Yes";
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
	string s;
	cin>>s;
	int cnt=0;
	int n=s.size();
	bool st=true;
	for(int i=1;i<n;i++)
	{
		if(s[i]>='A'&&s[i]<='Z')
		{
			st=false;	
		}	
	} 
	if(st&&s[0]>='A'&&s[0]<='Z')
	{
		cout<<"Yes";
	}
	else
	{
		cout<<"No";
	}
	return 0;
}