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
import datetime
F = []
for i in range(0, 60):
	F.append([])
F[0].append(1)
for i in range(1, 60):
	F[0].append(F[0][i-1]*i)
for i in range(1, 60):
	for j in range(60):
		if j > i:
			F[i].append(j*F[i][j-1])
		else:
			F[i].append(1)
n, m, t = map(int, raw_input().split())
# for i in range(5):
# 	print(F[0][i])
# 	for j in range(10):
# 		print(F[i][j])
ans = 0
for i in range(max(4, t-m), min(t, n+1)):
	# print(i, F[n-i][n], F[0][i], t-i, F[m-(t-i)][m],F[0][t-i])
	ans +=(F[n-i][n]/F[0][i] * F[m-(t-i)][m]/F[0][t-i])
print(ans)