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 C++14 (GCC 5.4.1) (judge verdict: Accepted)


#include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>
#include <stack>
#include <queue>
#include <functional>
#include <limits.h>
#include <set>
#include <map>
#include <tuple>
using namespace std;

#define ll long long
#define ull unsigned long long
#define rep(i,N) for (int i=0;i<N;i++)
#define loop(i,N,M) for(int i=N;i<M;i++)
#define MAX(v) *max_element(v.begin(),v.end())
#define MIN(v) *min_element(v.begin(),v.end())
#define SORTL2S(type,v) sort(v.begin(),v.end(),greater<type>())
#define SORTS2L(type,v) sort(v.begin(),v.end())
#define SORTMF(v,func) sort(v.begin(),v.end(),func)

//変数
ll N,H,W;
vector<ll> vec;


//解法
void solve() {
	
	cout << (N - H + 1) * (N - W + 1);

	return;
}

int main() {
	//入力

	cin >> N>>H>>W;

	solve();
	cout << endl;
	return 0;
}