Java解答

import java.util.Scanner;


public class Main {  
  public static void main(String args[]) throws Exception {  
  Scanner in=new Scanner(System.in);
  int a=in.nextInt(); 
  double e = 1.0;  
    double t = 1.0;  
    for (int i = 1; i <= a; i++) {  
      t /= i;  
      e += t;  
    }  
    System.out.println(e);  
    
  }
}