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
def calcularCombinacao(n, k):
    res = 1
    for i in range(1, k + 1):
        res = res * (n - k + i) // i
    return res

entrada = input().split()
numMeninos = int(entrada[0])
numMeninas = int(entrada[1])
tamGrupo = int(entrada[2])

res = 0
i = 4
j = tamGrupo - i
while i <= numMeninos and j >= 1:
    res += calcularCombinacao(numMeninos, i) * calcularCombinacao(numMeninas, j)
    i += 1
    j -= 1

print(res)
  	 	    		  	 	   	  	 							