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 combination(n,r):
    s=1
    for j in range(r):
        a=j+1
        b=n-j
        s=(s*b)//a
    return s
n,m,t=list(map(int,input().split()))
x=n-3
y=m
z=t-4
ans1=0
ans2=0
p=min(x,y,z)
for i in range(p):
    ans1+=(combination(n,4+i)*combination(m,t-4-i))
    ans2+=(combination(m,1+i)*combination(n,t-1-i))
print(max(ans1,ans2))