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
maxn = 101;
c = [[0 for col in range(maxn)] for row in range(maxn)]
gt = list()
def init():       
    for i in range(1,maxn):
        c[1][i] = i
        c[i][0] = 1
    for j in range(2,maxn):
        for i in range(2,j+1):
            if i>j:
                break
            c[i][j] = c[i-1][j-1] + c[i][j-1]
    for i in range(0,maxn):
        c[0][i] = 1

def solve():
    n,m,t = raw_input().split()
    n = int(n)
    m = int(m)
    t = int(t)
    res = 0
    for g in range(1,m+1):
        for b in range(4,n+1):
            if (g+b == t):
                res = res + c[g][m]*c[b][n]
    print res

init()
solve()
