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
v = raw_input().split()
n = int(v[0])
m = int(v[1])
t = int(v[2])
res = 0
for i in range(4, t):
    a = 1
    for j in range(n-i+1, n+1):
        a = a*j 
    for j in range(1, i+1):
        a = a/j
    b = 1
    k = t-i
    for j in range(m-k+1, m+1):
        b = b*j
    for j in range(1, k+1):
        b = b/j
    res = res + a*b
print str(res)