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
#!/usr/bin/env python3
ans = 0
C = []
for k in range(31):
	C.append([0] * 31)
C[0][0] = 1
for k in range(1, 31):
	C[k][0] = 1
	for i in range(1, k + 1):
		C[k][i] = C[k - 1][i] + C[k - 1][i - 1]
n, m, t = map(int, input().split())
for k in range(4, n + 1):
	if 1 <= t - k <= m:
		ans += C[n][k] * C[m][t - k]
print(ans)
