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 p[] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37};
int mm[16];
void mult(int a, int m) {
  int i;
  for (i = 0; a > 1; ++i) {
    while (a % p[i] == 0) {
      a /= p[i];
      mm[i] += m;
    }
  }
}
long long calc() {
  long long res = 1;
  for (int i = 0; i < 10; ++i) {
    for (int j = 0; j < mm[i]; ++j) {
      res *= p[i];
    }
  }
  return res;
}
void clear() { memset(mm, 0, sizeof(mm)); }
long long binom(long long n, long long k) {
  clear();
  int i;
  for (i = k + 1; i <= n; ++i) {
    mult(i, 1);
  }
  for (i = 1; i <= n - k; ++i) {
    mult(i, -1);
  }
  return calc();
}
int main() {
  int i, j;
  int n, m, t;
  long long res = 0;
  cin >> n >> m >> t;
  for (i = 4; i < t; ++i) {
    if (t - i > m || i > n) continue;
    long long cur = binom(n, i);
    cur *= binom(m, t - i);
    res += cur;
  }
  cout << res << endl;
  return 0;
}
