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())

dp = []

for i in range(0,32 , 1):
    dp.append(0)
dp[0] = 1

for i in range(1 , 32 , 1):
    dp[i] = i * dp[i-1]
girl = 0
ans = 0
for i in range(max(t - m  , 4), n+1, 1):
    g = t - i
    if g == 0 :
        break
    else:
       ans += (int(dp[n] / int(dp[i] * dp[n-i])) * int(dp[m] / int(dp[g] * dp[m-g]) ))

print(int(ans)) 

