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 Python (3.4.3) (judge verdict: Runtime Error)

import itertools
import sys
sys.setrecursionlimit(2000)
h, w = map(int, input().split())
s_list = []
for i in range(h):
  s_list.append(list(input()))
res = 0
check_list = set()

def rec_create_area(point, tmp_area, current_str):
  new_point_list = []
  new_point_list.append((point[0] + 1, point[1]))
  new_point_list.append((point[0], point[1] + 1))
  new_point_list.append((point[0] - 1, point[1]))
  new_point_list.append((point[0], point[1] - 1))
  for new_point in new_point_list:
    if new_point[0] >= h or new_point[1] >= w or new_point[0] < 0 or new_point[1]  < 0:
      continue
    if new_point in check_list:
      continue
    new_str = s_list[new_point[0]][new_point[1]]
    if new_str == current_str:
      continue
    if new_str == "#":
      tmp_area[0] += 1
    else:
      tmp_area[1] += 1
    check_list.add(new_point)
    rec_create_area(new_point, tmp_area, new_str)
  
for a, b in itertools.product(range(h), range(w)):
  check_point = (a, b)
  if check_point in check_list:
    continue
  check_list.add(check_point)
  current_str = s_list[check_point[0]][check_point[1]]
  if current_str == "#":
    tmp_area = [1, 0]
  else:
    tmp_area = [0, 1]
  rec_create_area(check_point, tmp_area, current_str)
  res += tmp_area[0] * tmp_area[1]
  
print(res)