There are n boys and m girls attending a theatre club. To set a play "The Big Bang Theory", they need to choose a group containing exactly t actors containing no less than 4 boys and no less than one girl. How many ways are there to choose a group? Of course, the variants that only differ in the composition of the troupe are considered different.

Perform all calculations in the 64-bit type: long long for С/С++, int64 for Delphi and long for Java.

Input

The only line of the input data contains three integers n, m, t (4 ≤ n ≤ 30, 1 ≤ m ≤ 30, 5 ≤ t ≤ n + m).

Output

Find the required number of ways.

Please do not use the %lld specificator to read or write 64-bit integers in С++. It is preferred to use cin, cout streams or the %I64d specificator.

Examples

Input

5 2 5


Output

10


Input

4 3 5


Output

3
n, m, t = map(int, input().split())

c = 31 * [0]
for i in range(31):
  r = 31 * [0]
  r[0] = 1
  r[i] = 1
  c[i] = r

for i in range(1, 31):
  for j in range(1, i + 1):
    c[i][j] = c[i - 1][j] + c[i - 1][j - 1]

res = 0
for i in range(4, t):
  if (i <= n and t - i <= m):
    res += c[n][i] * c[m][t-i]

print(res)

 	 	   		 	 	 		 	   			  					