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 fact[40], inv[40];
long long n, m, t;
long long fp(long long b, long long e) {
  if (e == 0) return 1;
  long long ans = fp(b, e / 2);
  ans = (ans * ans) % 1000000007;
  if (e % 2 != 0) ans = (ans * (b % 1000000007)) % 1000000007;
  return ans;
}
void factninv(long long n) {
  fact[0] = inv[0] = 1;
  for (long long i = 1; i <= n; i++) {
    fact[i] = (fact[i - 1] * i) % 1000000007;
    inv[i] = fp(fact[i], 1000000007 - 2);
  }
}
long long ncr(long long n, long long r) {
  return ((fact[n] * inv[r]) % 1000000007 * inv[n - r]) % 1000000007;
}
int main() {
  cin >> n >> m >> t;
  long long ans = 0;
  long long b, g;
  if (n + m == t) {
    cout << 1;
    return 0;
  }
  factninv(30);
  for (int k = 4; k <= n; k++) {
    int gn = t - k;
    if (k >= 4 && gn >= 1 && gn <= m) {
      b = ncr(n, k);
      g = ncr(m, gn);
      ans += b * g;
    }
  }
  cout << ans;
  return 0;
}
