public static void main ( String [ ] args ) {
  Scanner input = new Scanner ( System . in ) ;
  long n = input . nextInt ( ) ;
  long d = input . nextInt ( ) ;
  long m = input . nextInt ( ) ;
  long l = input . nextInt ( ) ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    long s1 = ( i - 1 ) * m + l ;
    long s2 = i * m ;
    long s3 = ( s1 / d ) * d + d ;
    if ( i == n || s3 < s2 ) {
      System . out . println ( s3 ) ;
      return ;
    }
  }
}

public static void main ( String [ ] args ) { Scanner input = new Scanner ( System . in ) ; long n = input . nextInt ( ) ; long d = input . nextInt ( ) ; long m = input . nextInt ( ) ; long l = input . nextInt ( ) ; for ( int i = 1 ; i <= n ; i ++ ) { long s1 = ( i - 1 ) * m + l ; long s2 = i * m ; long s3 = ( s1 / d ) * d + d ; if ( i == n || s3 < s2 ) { System . out . println ( s3 ) ; 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)))) (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)))) (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 (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (identifier)) right: (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (identifier) right: (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) right: (identifier)) right: (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (binary_expression left: (identifier) right: (identifier)))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) (return_statement)))))))