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
from math import*
n,m,t = map(int,input().split())
summ = 0
if (m+n==t):
    print('1')
elif (m == 1):
    z = 1
    a = t - m
    while(z>0):
        x = int(factorial(n)/(factorial(a)*factorial(n-a)))
        y = int(factorial(m)/(factorial(t-a)*factorial(m-(t-a))))
        summ = int(summ + x*y)
        a = a+1
        z = int(z - 1)
    print(summ)
    
elif (n == 4):
    z = 1
    a = t - n
    while(z>0):
        x = int(factorial(m)/(factorial(a)*factorial(m-a)))
        y = int(factorial(n)/(factorial(t-a)*factorial(n-(t-a))))
        summ = int(summ + x*y)
        a = a+1
        z = int(z - 1)
    print(summ)
    
elif (t-m>=4 and t-n>1):
    z = (m+n-t)+1
    a = t - m
    while(z>0):
        x = int(factorial(n)/(factorial(a)*factorial(n-a)))
        y = int(factorial(m)/(factorial(t-a)*factorial(m-(t-a))))
        summ = int(summ + x*y)
        a = a+1
        z = int(z - 1)
    print(summ)
elif (t-m<4 and t-n<=1):
    z = t-4
    a = 4
    while(z>0):
        x = int(factorial(n)/(factorial(a)*factorial(n-a)))
        y = int(factorial(m)/(factorial(t-a)*factorial(m-(t-a))))
        summ = int(summ + x*y)
        a = a+1
        z = int(z - 1)
    print(summ)

elif (t-m>4 and t-n<1):
    z = (m-1)+1
    a = 1
    while(z>0):
        x = int(factorial(m)/(factorial(a)*factorial(m-a)))
        y = int(factorial(n)/(factorial(t-a)*factorial(n-(t-a))))
        summ = int(summ + x*y)
        a = a+1
        z = int(z - 1)
    print(summ)

elif (t-m<4 and t-n>1):
    z = (n-4)+1
    a = 4
    while(z>0):
        x = int(factorial(n)/(factorial(a)*factorial(n-a)))
        y = int(factorial(m)/(factorial(t-a)*factorial(m-(t-a))))
        summ = int(summ + x*y)
        a = a+1
        z = int(z - 1)
    print(summ)

