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;
template <class T1>
void deb(T1 e) {
  cout << e << endl;
}
template <class T1, class T2>
void deb(T1 e1, T2 e2) {
  cout << e1 << " " << e2 << endl;
}
template <class T1, class T2, class T3>
void deb(T1 e1, T2 e2, T3 e3) {
  cout << e1 << " " << e2 << " " << e3 << endl;
}
template <class T1, class T2, class T3, class T4>
void deb(T1 e1, T2 e2, T3 e3, T4 e4) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << endl;
}
template <class T1, class T2, class T3, class T4, class T5>
void deb(T1 e1, T2 e2, T3 e3, T4 e4, T5 e5) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << " " << e5 << endl;
}
template <class T1, class T2, class T3, class T4, class T5, class T6>
void deb(T1 e1, T2 e2, T3 e3, T4 e4, T5 e5, T6 e6) {
  cout << e1 << " " << e2 << " " << e3 << " " << e4 << " " << e5 << " " << e6
       << endl;
}
long long sqr(long long n) { return n * n; }
double LOG(long long a, long long b) { return (log(a) / log(b)); }
long long GCD(long long a, long long b) {
  if (a < 0) return GCD(-a, b);
  if (b < 0) return GCD(a, -b);
  return (!b) ? a : GCD(b, a % b);
}
long long LCM(long long a, long long b) {
  if (a < 0) return LCM(-a, b);
  if (b < 0) return LCM(a, -b);
  return (a * (b / GCD(a, b)));
}
long long BigMod(long long B, long long P, long long M) {
  if (!P) return 1;
  if (!(P % 2)) return sqr(BigMod(B, P / 2, M)) % M;
  return (B % M) * (BigMod(B, P - 1, M)) % M;
}
long long findNcr(int n, int r) {
  long long res = 1ll;
  r = min(r, n - r);
  int i, j;
  for (i = 1, j = n; i <= r; i++, j--) {
    res *= j;
    res /= i;
  }
  return res;
}
int main(void) {
  int n, m, k;
  cin >> n >> m >> k;
  long long res = 0ll;
  int i;
  for (i = 4; i <= n; i++) {
    if (k - i >= 1 && k - i <= m) res += findNcr(n, i) * findNcr(m, k - i);
  }
  deb(res);
  return 0;
}
