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 comb[100][100];
long long nCr(long long n, long long r) {
  if (n < 0 || r < 0) return 0;
  long long &ans = comb[n][r];
  if (n < r) return 0;
  if (n == r || r == 0) return 1;
  if (ans != -1) return ans;
  ans = (nCr(n, r - 1) * (n - r + 1)) / (r);
  return ans;
}
int32_t main() {
  memset(comb, -1, sizeof comb);
  long long boy, girl, team;
  cin >> boy >> girl >> team;
  long long tot = nCr(boy + girl, team);
  long long unvalid = nCr(boy, team);
  for (long long i = 0; i < 4; i++) {
    unvalid += nCr(girl, team - i) * nCr(boy, i);
  }
  cout << tot - unvalid;
}
