#include <bits/stdc++.h>
#include <string>
#define ft first
#define sc second
#define pt(sth) cout << sth << "\n"
#define chmax(a, b) (a)=max(a, b)
#define chmin(a, b) (a)=min(a, b)
#define moC(a, s, b) (a)=((a)s(b)+MOD)%MOD
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
static const ll INF=1e18;
static const ll MAX=101010;
static const ll MOD=1e9+7;


/*
 for(i=0; i<N; i++)
   cin >> a[i];
*/



int main(void) {
  ll i, j, k;
  
  char s[111];
  fgets(s, 105, stdin);
  
  ll e[26]={};
  ll N=strlen(s)-1;
  
  for(i=1; i<N; i+=2) {
    if(s[i]==' ') continue;
    e[s[i]-'a']=1;
  }
  
  ll f[111];
  memset(f, 1, sizeof(f));
  for(i=0; i<N; i++) {
    if(e[s[i]-'a']) f[i]=0;
    if(s[i]==' ') f[i]=0;
  }
  
  for(i=0; i<N; i+=2) if(!f[i]) {pt("No"); return 0;}
  pt("Yes");
  
}