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>
long long cewe, n, m, t, i, j;
long long A[50][50];
long long jawaban;
using namespace std;
void factorial() {
  A[0][0] = 1;
  for (i = 1; i <= 40; i++) {
    A[i][0] = 1;
    A[i][i] = 1;
  }
  for (i = 1; i <= 40; i++) {
    for (j = 1; j <= i - 1; j++) {
      A[i][j] = A[i - 1][j - 1] + A[i - 1][j];
    }
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  factorial();
  cin >> n >> m >> t;
  jawaban = 0;
  for (i = 4; i <= t - 1; i++) {
    cewe = t - i;
    if (n >= i && m >= cewe) jawaban += A[n][i] * A[m][cewe];
  }
  cout << jawaban << endl;
}
