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 ans;
int i, j, n, m, t;
long long cnk(int n, int m) {
  long long res = 0;
  long long c[100];
  for (int i = 0; i < 100; i++) c[i] = 0;
  c[0] = 1;
  for (int i = 1; i <= m; i++) {
    for (j = n; j > 0; j--) {
      c[j] += c[j - 1];
    }
  }
  return c[n];
}
int main() {
  scanf("%d%d%d", &n, &m, &t);
  for (int i = 1; i <= m; i++) {
    int j = t - i;
    if (j <= n && j >= 4) {
      ans += cnk(i, m) * cnk(j, n);
    }
  }
  printf("%I64d", ans);
}
