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
import math
import itertools

n,m,t=map(int,(raw_input()).split())


p=[]
for i in range(0,40):
    p.append([0]*40)

p[0][0]=1
for i in range(1,40):
    p[i][0]=1
    for j in range(1,i+1):
        p[i][j]=p[i-1][j]+p[i-1][j-1]

ans=0
for i in range(4,n+1):
    for j in range(1,m+1):
        if i+j == t:
            ans+=p[n][i]*p[m][j]
print ans
