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, t = map(int, input().split())
fact = [0]*(n+m)
fact[0] = 1
for i in range(1, n+m):
    fact[i] = i*fact[i-1]
ans = 0
for b in range(4, n+1):
    g = t-b
    if g<1:
        break
    if g>m:
        continue
    ans += fact[n]*fact[m]//fact[n-b]//fact[b]//fact[m-g]//fact[g]
print(int(ans))
