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,k=map(int,input().split())
l=[]
l.append(1)
l.append(1)
an=0
for i in range(2,31,1):
    l.append(l[i-1]*i)
for i in range(4,k+1,1):
    x=0
    y=0
    if(i<=n):
        x=l[n]//(l[i]*l[n-i])
    if(k-i<=m and k-i>=1):
        y=l[m]//(l[k-i]*l[m-k+i])
    an+=x*y
print(an)
    


  