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
n, m, t = map(int, raw_input().split())

ncr = [[1 for i in range(61)] for j in range(61)]
for i in range(61):
    ncr[i][1] = i
    ncr[i][i] = 1

for i in range(1, 61):
    for j in range(2, i):
        ncr[i][j] = ncr[i-1][j] + ncr[i-1][j-1]

# why is this wrong
# print ncr[n][4] * m * ncr[n+m-5][t-5]

ans = 0
for b in range(4, n+1):
    g = t-b
    if b >= 4 and g >= 1 and g <= m and b+g == t:
        ans += ncr[n][b] * ncr[m][g]
print ans
