#include<bits/stdc++.h>
using namespace std;
#define IO ios_base::sync_with_stdio(0), cin.tie(0),cout.tie(0)
typedef long long ll;
const int N = 1e5 + 4 , MOD = 1e9 + 7 ;
string s ;
bool ok ;
bool solve(int idx)
{
if(idx == s.size()+1)
return (ok == 1) ;
if(idx % 2 == 0 && islower(s[idx]) || idx % 2 == 1 && isupper(s[idx]))
ok = 0 ;
solve(idx + 1) ;
return (ok == 1 ) ;
}
int main() {
IO ;
cin>>s ;
ok = 1 ;
s = '*' + s ;
if(solve(1) == 1)
cout<<"Yes" ;
else
cout<<"No" ;
return 0;
}
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