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
#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long nck(long long n, long long k) {
  long long res = 1, D, i;
  if (n < k) return 0;
  if (k > n - k) k = n - k;
  for (int i = 1; i <= k; i++) {
    D = gcd(res, i);
    res /= D;
    res *= (n - i + 1) / (i / D);
  }
  return res;
}
int main() {
  long long n = ({
    int t;
    scanf("%d", &t);
    t;
  }),
            m = ({
              int t;
              scanf("%d", &t);
              t;
            }),
            t = ({
              int t;
              scanf("%d", &t);
              t;
            }),
            res = 0;
  for (int b = 4; b <= n; b++) {
    int g = t - b;
    if (g >= 1 && g <= m) res += nck(n, b) * nck(m, g);
  }
  cout << res << endl;
}
