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 n, m, k;
long long ans = 0;
long long gcd(long long a, long long b) {
  while (a && b)
    if (a > b)
      a %= b;
    else
      b %= a;
  return a + b;
}
long long c(long long n, long long k) {
  int q = n - k, w = k;
  if (q > w) swap(q, w);
  int a[100], b[100];
  for (int i = w + 1; i <= n; i++) a[i] = i;
  for (int i = 2; i <= q; i++) b[i] = i;
  for (int i = 2; i <= q; i++)
    for (int j = w + 1; j <= n; j++) {
      long long z = gcd(a[j], b[i]);
      if (z == 1) continue;
      a[j] /= z;
      b[i] /= z;
    }
  long long ans = 1, f = 1;
  for (int j = w + 1; j <= n; j++) ans = ans * a[j];
  for (int i = 2; i <= q; i++)
    if (b[i] > 1) f = f * b[i];
  return ans / f;
}
int main() {
  cin >> n >> m >> k;
  for (int b = 4; b <= n; b++)
    for (int g = 1; g <= m; g++) {
      if (b + g == k)
        ans = ans + (long long)((long long)c(n, b) * (long long)c(m, g));
    }
  cout << ans;
  fclose(stdin);
  fclose(stdout);
  return 0;
}
