text: /*numPass=9, numTotal=9
  Verdict:ACCEPTED, Visibility:1, Input:"5
  abcde", ExpOutput:"Good String", Output:"Good String"
  Verdict:ACCEPTED, Visibility:1, Input:"8
  pqrsabcd", ExpOutput:"Good String", Output:"Good String"
  Verdict:ACCEPTED, Visibility:1, Input:"4
  azpg", ExpOutput:"Not Good String", Output:"Not Good String"
  Verdict:ACCEPTED, Visibility:1, Input:"7
  labexam", ExpOutput:"Not Good String", Output:"Not Good String"
  Verdict:ACCEPTED, Visibility:0, Input:"8
  aaaazzzz", ExpOutput:"Good String", Output:"Good String"
  Verdict:ACCEPTED, Visibility:0, Input:"6
  abczpq", ExpOutput:"Not Good String", Output:"Not Good String"
  Verdict:ACCEPTED, Visibility:0, Input:"6
  abcpqz", ExpOutput:"Not Good String", Output:"Not Good String"
  Verdict:ACCEPTED, Visibility:0, Input:"8
  acegikmo", ExpOutput:"Good String", Output:"Good String"
  Verdict:ACCEPTED, Visibility:0, Input:"ab", ExpOutput:"Good String", Output:"Good String"
  */
  #include <stdio.h>
  #include <stdlib.h>
  int mod(int n)
  {
      if(n<0)
          n=-n;
      return n;
  }
  int main()
  {
      int n,i,j,count=0,a,b;
      char *s;
      scanf("%d",&n);
      s=(char*)malloc((n+1)*sizeof(char));
      scanf("%s",s);
      if(n>1)
      {
          for(i=1,j=n-1;i<n;i++,j--)
          {
              a=s[i]-s[i-1];
              b=s[j-1]-s[j];
              a=mod(a);
              b=mod(b);
              if(a==b)
                  count++;
          }
          if(count==n-1)
              printf("Good String");
          else
              printf("Not Good String");
      }
      else if(n==0)
          printf("Good String");
      return 0;
  }