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 binomialCoefficient(n, k): 
    # since C(n, k) = C(n, n - k) 
    if(k > n - k): 
        k = n - k 
    # initialize result 
    res = 1
    # Calculate value of  
    # [n * (n-1) *---* (n-k + 1)] / [k * (k-1) *----* 1] 
    for i in range(k): 
        res = res * (n - i) 
        res = res // (i + 1) 
    return res 
#q=int(input())
q=1
for _ in range(q):
    n,m,t=map(int,input().split())
    ans=0
    for i in range(1,t-3):
        if i<=m and t-i<=n:
            p1=binomialCoefficient(m,i)
            p2=binomialCoefficient(n,t-i)
            ans+=(p1*p2)
    print(int(ans))    
    
    
    
    