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
cnk = [[0]*100 for i in range(100)]
for i in range(100):
    for j in range(100):
        if (i == 0 and j == 0):
            cnk[i][j] = 1
        elif (i == 0) and (j != 0):
            cnk[i][j] = 0
        elif (i == j):
            cnk[i][j] = 1
        elif (j == 0):
            cnk[i][j] = 1
        else:
            cnk[i][j] = cnk[i-1][j] + cnk[i-1][j-1]

n, m, t = map(int, raw_input().split())
res = 0
for b in range(4, n+1):
    g = t - b
    if b < 4 or g < 1:
        continue
    res += cnk[n][b] * cnk[m][g]
print res