public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int m = sc . nextInt ( ) ;
  sc . nextLine ( ) ;
  String [ ] str = new String [ n ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    str [ i ] = sc . nextLine ( ) ;
  }
  boolean flag1 , flag2 ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    flag2 = true ;
    for ( int j = 0 ;
    j < m ;
    j ++ ) {
      if ( str [ i ] . charAt ( j ) == '1' ) {
        flag1 = false ;
        for ( int k = 0 ;
        k < n ;
        k ++ ) {
          if ( str [ k ] . charAt ( j ) == '1' && k != i ) {
            flag1 = true ;
            break ;
          }
        }
        if ( ! flag1 ) flag2 = false ;
      }
    }
    if ( flag2 ) {
      System . out . println ( "YES" ) ;
      return ;
    }
  }
  System . out . println ( "NO" ) ;
  return ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int m = sc . nextInt ( ) ; sc . nextLine ( ) ; String [ ] str = new String [ n ] ; for ( int i = 0 ; i < n ; i ++ ) { str [ i ] = sc . nextLine ( ) ; } boolean flag1 , flag2 ; for ( int i = 0 ; i < n ; i ++ ) { flag2 = true ; for ( int j = 0 ; j < m ; j ++ ) { if ( str [ i ] . charAt ( j ) == '1' ) { flag1 = false ; for ( int k = 0 ; k < n ; k ++ ) { if ( str [ k ] . charAt ( j ) == '1' && k != i ) { flag1 = true ; break ; } } if ( ! flag1 ) flag2 = false ; } } if ( flag2 ) { System . out . println ( " YES " ) ; return ; } } System . out . println ( " NO " ) ; return ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (type_identifier) dimensions: (dimensions_expr (identifier))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))) (local_variable_declaration type: (boolean_type) declarator: (variable_declarator name: (identifier)) declarator: (variable_declarator name: (identifier))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (identifier) right: (true))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (false))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (identifier))) right: (character_literal)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (block (expression_statement (assignment_expression left: (identifier) right: (true))) (break_statement))))) (if_statement condition: (parenthesized_expression (unary_expression operand: (identifier))) consequence: (expression_statement (assignment_expression left: (identifier) right: (false)))))))) (if_statement condition: (parenthesized_expression (identifier)) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (return_statement))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (return_statement)))