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;
const int MAXN = 10 + 10000;
const int INF = int(1e9);
int n, m, t;
long long tohop(int n, int k) {
  long long c = 1;
  for (int i = 1; i <= k; i++, n--) {
    c = c * n / i;
  }
  return c;
}
int main() {
  n = ({
    int n;
    scanf(" %d ", &n);
    n;
  });
  m = ({
    int n;
    scanf(" %d ", &n);
    n;
  });
  t = ({
    int n;
    scanf(" %d ", &n);
    n;
  });
  long long res = 1;
  for (int i = (4), _b = (t); i < t; ++i) {
    int j = t - i;
    res += tohop(n, i) * tohop(m, j);
  }
  printf("%I64d", res - 1);
  return 0;
}
