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 store[60][60];
long long binomialCoeff(long long n, long long k) {
  if (store[n][k]) return store[n][k];
  if (k == 0 || k == n || n == 0) return 1;
  store[n][k] = binomialCoeff(n - 1, k - 1) + binomialCoeff(n - 1, k);
  return store[n][k];
}
int main() {
  long long n, m, t, ans = 0;
  cin >> n >> m >> t;
  long long n1, n2, m2, t2, m1, t1;
  n1 = 4;
  m1 = 1;
  t1 = t - 5;
  if (t1 - (m - 1) > 0) {
    m1 = m;
    t1 -= (m - 1);
    n1 += t1;
  } else {
    m1 += t1;
  }
  n2 = 4;
  m2 = 1;
  t2 = t - 5;
  if (t2 - (n - 4) > 0) {
    n2 = n;
    t2 -= (n - 4);
    m2 += t2;
  } else {
    n2 += t2;
  }
  while (n1 + m1 == t && n1 <= n2) {
    ans += binomialCoeff(n, n1) * binomialCoeff(m, m1);
    n1++;
    m1--;
  }
  if (n + m == t) ans = 1;
  cout << ans << endl;
  return 0;
}
