public static void main ( String args [ ] ) {
  Scanner in = new Scanner ( System . in ) ;
  int n = in . nextInt ( ) ;
  int d = in . nextInt ( ) ;
  String s ;
  int max = - 1 , m = 0 ;
  for ( int i = 0 ;
  i < d ;
  i ++ ) {
    s = in . next ( ) ;
    if ( s . indexOf ( "0" ) >= 0 ) m ++ ;
    else {
      if ( m > max ) max = m ;
      m = 0 ;
    }
  }
  if ( m > max ) max = m ;
  System . out . println ( max ) ;
}

public static void main ( String args [ ] ) { Scanner in = new Scanner ( System . in ) ; int n = in . nextInt ( ) ; int d = in . nextInt ( ) ; String s ; int max = - 1 , m = 0 ; for ( int i = 0 ; i < d ; i ++ ) { s = in . next ( ) ; if ( s . indexOf ( "0" ) >= 0 ) m ++ ; else { if ( m > max ) max = m ; m = 0 ; } } if ( m > max ) max = m ; System . out . println ( max ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier) dimensions: (dimensions))) 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)))) (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (unary_expression operand: (decimal_integer_literal))) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (string_literal))) right: (decimal_integer_literal))) consequence: (expression_statement (update_expression (identifier))) alternative: (block (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (expression_statement (assignment_expression left: (identifier) right: (identifier)))) (expression_statement (assignment_expression left: (identifier) right: (decimal_integer_literal))))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (expression_statement (assignment_expression left: (identifier) right: (identifier)))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))