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 pre[10000];
long long gcd(long long a, long long b) {
  if (a % b == 0) return b;
  return gcd(b, a % b);
}
long long cal(long long n, long long r) {
  long long i, j, k, s, g, d;
  for (i = 0; i <= n; i++) {
    pre[i] = i;
  }
  for (i = 0; i <= r; i++) pre[i] = 1;
  for (i = 1; i <= n - r; i++) {
    d = i;
    for (j = r + 1; j <= n; j++) {
      g = gcd(pre[j], d);
      pre[j] /= g;
      d /= g;
      if (d == 1) break;
    }
  }
  s = 1;
  for (i = 1; i <= n; i++) {
    s *= pre[i];
  }
  return s;
}
int main() {
  long long i, j, k, s, d, r, m, n, t;
  cin >> n >> m >> t;
  s = n + m;
  long long wg, wog, w1, w2, w3, w0;
  wg = cal(s, t);
  if (n < t)
    wog = 0;
  else
    wog = cal(n, t);
  if (m >= t)
    w0 = cal(m, t);
  else
    w0 = 0;
  if (m >= t - 1)
    w1 = cal(n, 1) * cal(m, t - 1);
  else
    w1 = 0;
  if (m >= t - 2)
    w2 = cal(n, 2) * cal(m, t - 2);
  else
    w2 = 0;
  if (m >= t - 3)
    w3 = cal(n, 3) * cal(m, t - 3);
  else
    w3 = 0;
  cout << wg - (wog + w1 + w2 + w3 + w0) << endl;
  return 0;
}
