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