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
import sys
comb = [[1] * 40 for x in xrange(40)]
for x in xrange(2,40):
    for y in xrange(1,x):
        comb[x][y] = comb[x-1][y-1] + comb[x-1][y]
n, m, t = map(int, sys.stdin.readline().split())
ans = 0
for b in range(4, t):
    g = t - b
    if b > n or g > m: continue
    ans += comb[n][b] * comb[m][g]
print ans
