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 C(int n, int r) {
  if (r > n / 2) r = n - r;
  long long ans = 1;
  int i;
  for (i = 1; i <= r; i++) {
    ans *= n - r + i;
    ans /= i;
  }
  return ans;
}
int main() {
  long long int k = 0;
  int a, b, c, d, r1, r2, n1, n2, d1, d2;
  cin >> a >> b >> c;
  r1 = 4;
  for (int i = 0; i < c; i++) {
    if (c - r1 > b)
      r1++;
    else
      break;
  }
  r2 = c - r1;
  n1 = a, n2 = b;
  for (int i = 0; i < c; i++) {
    if (n1 == r1 || r2 == 1) {
      k += C(n1, r1) * C(n2, r2);
      cout << k;
      break;
    }
    k += C(n1, r1) * C(n2, r2);
    r1++, r2--;
  }
}
