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 sys
import math

def nCr(n,r):
    f = math.factorial
    return f(n) / f(r) / f(n-r)

n,m,t=map(int,input().split())
storq=[0 for i in range(n+1)]
storm=[0 for j in range(m+1)]
for i in range(0,n//2+1):
    k=int(round(nCr(n,i)))
    storq[i]+=k
    storq[n-i]+=k
    if(n%2==0 and i==n//2):
        storq[n-i]-=k
    #IOPIOPIOP
for j in range(0,m//2+1):
    p =int(round(nCr(m, j)))
    storm[j] += p
    storm[m - j] += p
    if (m % 2 == 0 and j == m // 2):
        storm[m - j] -= p

suman=0
mini=t-m
maxi=n+1
minj=t-n
for i in range(max(4,mini),min(maxi,t+1)):
    if (t - i >= 1):
        suman+=storq[i]*storm[t-i]
print(suman)