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 power(long long int x, long long int y, long long int p) {
  long long int res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long int modInverse(int n, int p) { return power(n, p - 2, p); }
long long int C(long long int n, long long int r) {
  long long int f = 1;
  for (long long int i = 0; i < r; i++) {
    f *= (n - i);
    f /= (i + 1);
  }
  return f;
}
int main() {
  long long int n, m, t, MOD = 1e9 + 7;
  long long int ans = 0;
  cin >> n >> m >> t;
  for (long long int b = 4; b <= n; b++) {
    long long int g = (t - b);
    if (g < 1) continue;
    ans += C(n, b) * C(m, g);
  }
  cout << ans;
}
