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>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
long long int ncr[31][31];
int main() {
  long long int n, m, t, i, j, ans = 0;
  cin >> n >> m >> t;
  ncr[1][0] = ncr[1][1] = 1;
  for (i = 2; i <= 30; i++) {
    for (j = 0; j < i; j++) {
      ncr[i][j] = ncr[i - 1][j] + ncr[i - 1][j - 1];
    }
    ncr[i][i] = 1;
  }
  for (i = 4; i <= n; i++) {
    long long int temp = t - i;
    if (temp > m or temp < 1)
      continue;
    else
      ans = ans + ncr[n][i] * ncr[m][temp];
  }
  cout << ans;
}
