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 = 60
a = [[0 for i in range(N)] for i in range(N)]
a[0][0] = 1
for n in range(1, N):
	for m in range(0,n+1):
		a[n][m] = a[n-1][m] + a[n-1][m-1]

n, m, t = map(int, input().split())
ans = 0
for x in range(4, n+1):
	if t-x < 1: continue
	ans += a[n][x] * a[m][t-x]
print(ans)
