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
factorial = [0 for i in range(31)]
factorial[0] = 1
for i in range(1,31):
    factorial[i] = factorial[i-1]*i

def choose(n,r):
    numerator = factorial[n]
    denominator = factorial[r] * factorial[n-r]
    return int(numerator/denominator)
    
    
n,m,t = map(int,input().split())
cnt = 0
for i in range(4, min(n,t)+1):
    k = t - i
    if((k>=1) and (k<=m)):
        ans = int(choose(n,i)*choose(m,k))
        cnt = cnt + ans

print(cnt)
        
        
        
