public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  int i , j ;
  i = input . nextInt ( ) ;
  j = input . nextInt ( ) ;
  ArrayList < String > m = new ArrayList < String > ( ) ;
  input . nextLine ( ) ;
  for ( int k = 0 ;
  k < i ;
  k ++ ) {
    m . add ( input . nextLine ( ) ) ;
  }
  ArrayList < Integer > light = new ArrayList < Integer > ( ) ;
  for ( int k = 0 ;
  k < j ;
  k ++ ) {
    light . add ( 0 ) ;
  }
  for ( int k = 0 ;
  k < m . size ( ) ;
  k ++ ) {
    for ( int l = 0 ;
    l < j ;
    l ++ ) {
      if ( m . get ( k ) . charAt ( l ) == '1' ) {
        light . set ( l , light . get ( l ) + 1 ) ;
      }
    }
  }
  for ( int k = 0 ;
  k < i ;
  k ++ ) {
    if ( is ( light , j , m , k ) ) {
      System . out . println ( "YES" ) ;
      return ;
    }
  }
  System . out . println ( "NO" ) ;
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; int i , j ; i = input . nextInt ( ) ; j = input . nextInt ( ) ; ArrayList < String > m = new ArrayList < String > ( ) ; input . nextLine ( ) ; for ( int k = 0 ; k < i ; k ++ ) { m . add ( input . nextLine ( ) ) ; } ArrayList < Integer > light = new ArrayList < Integer > ( ) ; for ( int k = 0 ; k < j ; k ++ ) { light . add ( 0 ) ; } for ( int k = 0 ; k < m . size ( ) ; k ++ ) { for ( int l = 0 ; l < j ; l ++ ) { if ( m . get ( k ) . charAt ( l ) == '1' ) { light . set ( l , light . get ( l ) + 1 ) ; } } } for ( int k = 0 ; k < i ; k ++ ) { if ( is ( light , j , m , k ) ) { System . out . println ( " YES " ) ; return ; } } System . out . println ( " NO " ) ; }
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