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;
int main() {
  long long int t, a, b, c, d, i, j, k, l, n, m, x, y, s, v, h, h1, h2;
  cin >> n >> m >> t;
  l = 1;
  k = 1;
  a = 1;
  b = 1;
  x = 1;
  j = 0;
  if (n >= t) {
    y = t - 1;
    x = 1;
  } else if (n < t) {
    x = t - n;
    y = n;
  }
  while (1) {
    k = 1;
    l = 1;
    a = 1;
    b = 1;
    if (y < 4 || x > m) break;
    h = n;
    for (i = 1; i <= y; i++) {
      l = l * h;
      k = k * i;
      if (l % k == 0) {
        l = l / k;
        k = 1;
      }
      --h;
    }
    h1 = m;
    for (i = 1; i <= x; i++) {
      a = a * h1;
      b = b * i;
      if (a % b == 0) {
        a = a / b;
        b = 1;
      }
      h1--;
    }
    s = l / k;
    v = a / b;
    j += (l * a);
    y--;
    x++;
  }
  cout << j;
}
