public static void main ( String [ ] args ) {
  Scanner in = new Scanner ( System . in ) ;
  int N = in . nextInt ( ) ;
  char [ ] S = in . next ( ) . toCharArray ( ) ;
  boolean noSolution = false ;
  boolean moreSolutions = S [ 0 ] == '?' || S [ N - 1 ] == '?' ;
  for ( int n = 1 ;
  n < N ;
  n ++ ) {
    if ( S [ n - 1 ] == S [ n ] ) {
      if ( S [ n ] == '?' ) {
        moreSolutions = true ;
      }
      else {
        noSolution = true ;
      }
    }
  }
  for ( int n = 2 ;
  n < N ;
  n ++ ) {
    if ( S [ n - 2 ] == S [ n ] && S [ n - 1 ] == '?' ) {
      moreSolutions = true ;
    }
  }
  boolean answer = ! noSolution && moreSolutions ;
  System . out . println ( answer ? "Yes" : "No" ) ;
}

public static void main ( String [ ] args ) { Scanner in = new Scanner ( System . in ) ; int N = in . nextInt ( ) ; char [ ] S = in . next ( ) . toCharArray ( ) ; boolean noSolution = false ; boolean moreSolutions = S [ 0 ] == ' ? ' || S [ N - 1 ] == ' ? ' ; for ( int n = 1 ; n < N ; n ++ ) { if ( S [ n - 1 ] == S [ n ] ) { if ( S [ n ] == ' ? ' ) { moreSolutions = true ; } else { noSolution = true ; } } } for ( int n = 2 ; n < N ; n ++ ) { if ( S [ n - 2 ] == S [ n ] && S [ n - 1 ] == ' ? ' ) { moreSolutions = true ; } } boolean answer = ! noSolution && moreSolutions ; System . out . println ( answer ? " Yes " : " No " ) ; }
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