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 = [int(x) for x in input().split()]
def nCr(n,r):
    numerator = 1
    denominator = 1
    for i in range(r):
        numerator = numerator*(n - i)
        denominator = denominator*(i + 1)
    return numerator//denominator
arrangements = 0
for boys in range(4,n + 1):
    girls = t - boys
    if girls >= 1 and girls <= m:
        arrangements += nCr(n,boys)*nCr(m,girls)  
    else:
        continue
if arrangements == 0:
    print(1)
else:
    print(arrangements)