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
ip = raw_input().split()

n = long(ip[0])
m = long(ip[1])
t = long(ip[2])

l = max(n,m)+1

a = [[0]*l for x in xrange(l)]

for i in range(l):
    for j in range(i+1):        
        if i == j or j == 0:
            a[i][j] = 1
        else:
            a[i][j] = a[i-1][j] + a[i-1][j-1]

s = 0
begin = max(t - m, 4) 
end = min(n, t-1)
for jj in range(begin,end+1):
    kk = t - jj
    s = s + a[n][jj] * a[m][kk]
print s    