A.cpp

/*****                                            American International University Bangladesh (AIUB)                                                          
                                                              Hadiur Rahman Nabil
                                                                  Z3R0-DAY[CF]
                                                               
                                                          
*****/
#include <bits/stdc++.h>
using namespace std;


int main() {


  int a,count=0;
 cin>>a;
 string s;
 cin>>s;
 for(int i=0; i<a; i++)
 {
     s[i]=towlower(s[i]);
     
 }
   sort(s.begin(),s.end());
   for(int i=0;i<a;i++)
   {
       if(s[i] != s[i+1])
       {
       
       count++;
       }
        
       
   }
   if(count==26)
   {
   cout<<"YES";
   }
   else
   {
       cout<< "NO";
   }



    return 0;
  }