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 long long OO = (long long)1e15;
const long long con = (long long)1e9 + 7;
vector<long long> v1;
map<char, int> ma;
set<long long> s1;
struct g {
  int a, b, c;
} g[100000];
long long c(long long n, long long k) {
  if (k == 0) return 1;
  return (n * c(n - 1, k - 1)) / k;
}
int main() {
  long long n, i, t, m, k;
  cin >> n >> m >> t;
  k = t - 4;
  long long s = 0;
  for (i = 1; i <= k; i++) {
    s += (c(m, i) * c(n, t - i));
  }
  cout << s;
  return 0;
}
