import java.util.*;
import java.lang.*;
import java.io.*;

// The main method must be in a class named "Main".
class Main {
    
    static void Printsum ( int i,int n ,int sum){
    
    
    
    
     if (i>n)
     {
     System.out.println(sum);
         return;
     }
     
        sum +=  i;  // s = sum + i
       Printsum(i+1,n,sum);
      
  
    }
    
    
    
    
    public static void main(String[] args) {
        System.out.println("sum n naturals number");
   
        Printsum(1,5,0);
   
 // we write three values  start  end or starting sum kya hoga 0
   
   
   
   
   
    }
}