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
input=sys.stdin.readline
fact=[1]*(65)
for i in range(1,65):
    fact[i]=fact[i-1]*(i)
def c(n,r):
    return(fact[n]//(fact[r]*fact[n-r]))
n,m,t=list(map(int,input().split()))
ans=0
for girls in range(1,t+1):
    boys=t-girls
    if boys>=4 and boys<=n and girls<=m:
        ans+=c(n,boys)*c(m,girls)
print(ans)