Problem:
Score : 100 points

Problem Statement

It has been decided that a programming contest sponsored by company A will be held, so we will post the notice on a bulletin board.

The bulletin board is in the form of a grid with N rows and N columns, and the notice will occupy a rectangular region with H rows and W columns.

How many ways are there to choose where to put the notice so that it completely covers exactly HW squares?

Constraints

1 \leq H, W \leq N \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
H
W

Output

Print the answer.

Sample Input 1

3
2
3

Sample Output 1

2

There are two ways to put the notice, as follows:

### ...
### ###
... ###

Here, # represents a square covered by the notice, and . represents a square not covered.

Sample Input 2

100
1
1

Sample Output 2

10000

Sample Input 3

5
4
2

Sample Output 3

8

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io;
//use std::collections::HashMap;
//use std::collections::BinaryHeap;
//use std::collections::HashSet;
//use std::mem; // mem::swap(&mut x,&mut y);
use std::cmp::{max}; // cmp::max,cmp::min

// Rust memo: https://hackmd.io/i0lQY1OKTDW1t66TECOmiw?both

#[allow(dead_code)]
fn read_line() -> String{
    let mut s = String::new();
    io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

#[allow(dead_code)]
fn read_charvec() -> Vec<char>{
    read_line().chars().collect()
}

#[allow(dead_code)]
fn read_ints() -> Vec<i64>{
    let s = read_line();
    let split:Vec<&str> = s.split(" ").collect();
    split.iter().map(|&x| x.to_string().parse().unwrap()).collect()
}

#[allow(dead_code)]
fn read_int() -> i64{
    read_ints()[0]
}

#[allow(dead_code)]
fn reverse(s: &String) -> String{
    s.chars().rev().collect::<String>()
}

#[allow(dead_code)]
fn read_lines(n:i64) -> Vec<String>{
    let mut xs = Vec::new();

    for _i in 0..n{
        xs.push(read_line());
    }

    xs
}

#[allow(dead_code)]
fn read_ints2(n:i64) -> Vec<i64>{
    read_lines(n).iter().map(|x| x.parse().unwrap()).collect()
}

#[allow(dead_code)]
fn arange(start:i64,end:i64,step:i64) -> Vec<i64>{
    let mut ret = Vec::new();
    let mut i = start;

    while i < end{
        ret.push(i);
        i += step;
    }

    ret
}

#[allow(dead_code)]
const DXS : [i64; 4] = [0,0,1,-1];
#[allow(dead_code)]
const DYS : [i64; 4]  = [1,-1,0,0];
#[allow(dead_code)]
const INF : i64 = 999999999;
#[allow(dead_code)]
const N_PRIME : i64 = 1000000007;

////////////////////////////////////////////////

fn main(){
    let n = read_int();
    let h = read_int();
    let w = read_int();
    let x1 = max(n+1-h,0);
    let x2 = max(n+1-w,0);

    println!("{}",x1*x2);
}