#include <bits/stdc++.h>          
using namespace std;
using ll = long long;
using ld = long double;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
#define repp(i, st, en) for (ll i = (ll)st; i < (ll)(en); i++)
#define repm(i, st, en) for (ll i = (ll)st; i >= (ll)(en); i--)
#define all(v) v.begin(), v.end()
void chmax(ll &x, ll y) {x = max(x,y);}
void chmin(ll &x, ll y) {x = min(x,y);}
void Yes() {cout << "Yes" << endl; exit(0);}
void No() {cout << "No" << endl; exit(0);}
template<class in_Cout> void Cout(in_Cout x) {cout << x << endl; exit(0);}

const ll inf = 1e18;
const ll mod = 1e9 + 7;

bool ABC(char c) {
    int i = c - 'A';
    return 0<=i && i<26;
}

bool abc(char c) {
    int i = c - 'a';
    return 0<=i && i<26;
}

int main() {
    string S; cin >> S;
    ll N = S.size();
    rep(i,N) {
        bool OK = false;
        if (i%2) OK = ABC(S[i]);
        else OK = abc(S[i]);
        if (!OK) No();
    }
    Yes();
}
#include <bits/stdc++.h>
using namespace std;

string f(string s){
    
    for(int i=0;i<s.size();i+=2){
        if(s[i]<'a' || s[i]>'z') return "No";
    }

for(int i=1;i<s.size();i+=2){
        if(s[i]<'A' || s[i]>'Z') return "No";
    }    
    return "Yes";
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    string s;
    cin>>s;
    
    cout<<f(s)<<endl;

}
