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())

pas = [[1]*i for i in range(1,62)]
for i in range(61):
    for j in range(1,i):
        pas[i][j]=pas[i-1][j-1]+pas[i-1][j]

ans = 0

ans += pas[n+m][t]

if t<=m:
    ans -= pas[m][t]
if (t-1)<=m:
    ans -= n*pas[m][t-1]
if (t-2)<=m:
    ans -= (n*(n-1))//2*(pas[m][t-2])
if (t-3)<=m:
    ans -= (n*(n-1)*(n-2))//6*(pas[m][t-3])
if t<=n:
    ans -= pas[n][t]

print(ans)