Is this a good solution strategy?

Write a program SumMain, that includes a recursive method computing the sum of the integers 1, 2, 3, …, N. The computation should be based on the following principle: the sum of the integers from 1 to N is equal to the sum of the integers from 1 to N/2 added with the sum of the integers from N/2+1 to N. **Is this a good solution strategy?**

__This is what i have done:__ I want opinions on the last part of the question, "Is this a good solution strategy?"

Thanks.

import java.io.*;

public class SumMain {

static int input;

static int sum = 0;

static int val;

static int first;

static int second;

public static void main(String args[])

{

try

{

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

System.out.print("Enter a number: ");

input = Integer.parseInt(br.readLine());

first = 1;

second = input/2;

val = calculate(first,second)+calculate(second+1,input);

System.out.println(val);

}

catch(Exception e)

System.out.println(e);

}

public static int calculate(int num, int n)

{

if(n==num)

return num;

else

{

return(n+calculate(num,n-1));

}

}

}