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 n, m, t, i, j, tot = 0, h, mx, mc, u;
long long solve(long long x, long long y, long long z) {
  long long sum = 1;
  while (x != y) {
    sum *= x;
    x--;
    if (sum % z == 0 && z != 1) {
      sum /= z;
      z--;
    }
  }
  while (z != 0) {
    sum /= z;
    z--;
  }
  return sum;
}
int main() {
  cin >> n >> m >> t;
  for (i = 4; i <= n; i++) {
    j = t - i;
    if (j <= m && j >= 1) {
      h = n - i;
      mx = max(h, i);
      u = m - j;
      mc = max(u, j);
      tot += solve(n, mx, h + i - mx) * solve(m, mc, u + j - mc);
    }
  }
  cout << tot;
  return 0;
}
