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())
b = [[0] * 61 for i in range(61)]

for i in range(61):
    b[i][0] = 1
    b[i][i] = 1
    
for i in range(61):
          for j in range(61):
                    if i > 0 and j > 0:
                        b[i][j] = b[i - 1][j] + b[i - 1][j - 1]

res = 0
i = 4
while i <= t - 1:
    res += b[n][i] * b[m][t - i];
    i += 1
print(res)