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;
inline long long in() {
  int32_t x;
  scanf("%d", &x);
  return x;
}
inline long long lin() {
  long long x;
  scanf("%lld", &x);
  return x;
}
const long long maxn = 1e6 + 10;
long long C[50][50], res;
int32_t main() {
  for (long long i = 0; i < 50; i++) {
    for (long long j = 0; j <= i; j++) {
      if (j == 0)
        C[i][j] = 1;
      else
        C[i][j] = C[i - 1][j] + C[i - 1][j - 1];
    }
  }
  long long n = in(), m = in(), t = in();
  for (long long i = 4; i <= n; i++)
    for (long long j = 1; j <= m; j++) {
      if (i + j == t) {
        res += C[n][i] * C[m][j];
      }
    }
  cout << res << endl;
}
