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, input().split())
c = [[0 for j in range(31)] for i in range(31)]
for i in range(31):
    c[i][0] = 1
    c[i][i] = 1
for i in range(1, 31):
    for j in range(1, 31):
        c[i][j] = c[i-1][j-1]+c[i-1][j]
# print(*c, sep = '\n')
ans = 0
for i in range(4, n+1):
    for j in range(1, m+1):
        if i+j == t:
            ans += c[n][i]*c[m][j]
print(ans)
