public static void main ( String [ ] args ) {
  Scanner omkar = new Scanner ( System . in ) ;
  int lines = omkar . nextInt ( ) ;
  long x = 0 ;
  long mult = 1 ;
  int temp ;
  int notMult = 0 ;
  Stack < Integer > stack = new Stack < Integer > ( ) ;
  String st ;
  for ( int i = 0 ;
  i < lines ;
  i ++ ) {
    st = omkar . next ( ) ;
    if ( st . charAt ( 0 ) == 'f' ) {
      temp = omkar . nextInt ( ) ;
      stack . push ( temp ) ;
      if ( mult < Math . pow ( 2 , 32 ) ) {
        mult = mult * temp ;
      }
      else {
        notMult ++ ;
      }
    }
    if ( st . charAt ( 0 ) == 'a' ) {
      x += mult ;
      if ( x >= Math . pow ( 2 , 32 ) ) {
        System . out . println ( "OVERFLOW!!!" ) ;
        return ;
      }
    }
    if ( st . charAt ( 0 ) == 'e' ) {
      if ( notMult > 0 ) {
        notMult -- ;
        stack . pop ( ) ;
      }
      else {
        mult = mult / stack . pop ( ) ;
      }
    }
  }
  System . out . println ( x ) ;
}

public static void main ( String [ ] args ) { Scanner omkar = new Scanner ( System . in ) ; int lines = omkar . nextInt ( ) ; long x = 0 ; long mult = 1 ; int temp ; int notMult = 0 ; Stack < Integer > stack = new Stack < Integer > ( ) ; String st ; for ( int i = 0 ; i < lines ; i ++ ) { st = omkar . next ( ) ; if ( st . charAt ( 0 ) == ' f ' ) { temp = omkar . nextInt ( ) ; stack . push ( temp ) ; if ( mult < Math . pow ( 2 , 32 ) ) { mult = mult * temp ; } else { notMult ++ ; } } if ( st . charAt ( 0 ) == ' a ' ) { x += mult ; if ( x >= Math . pow ( 2 , 32 ) ) { System . out . println ( " OVERFLOW ! ! ! " ) ; return ; } } if ( st . charAt ( 0 ) == ' e ' ) { if ( notMult > 0 ) { notMult -- ; stack . pop ( ) ; } else { mult = mult / stack . pop ( ) ; } } } System . out . println ( x ) ; }
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