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>
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
const long long MAX = 510000;
const long long INF = 1LL << 60;
const long long MOD = 1000000007LL;
using namespace std;
long long COM[61][61] = {};
void COMinit(void) {
  for (long long i = 0; i <= 60; i++) {
    for (long long j = 0; j <= i; j++) {
      if (j == 0 || j == i) {
        COM[i][j] = 1LL;
      } else {
        COM[i][j] = COM[i - 1][j - 1] + COM[i - 1][j];
      }
    }
  }
}
int main() {
  long long n, m, t;
  cin >> n >> m >> t;
  COMinit();
  long long res = 0;
  for (long long i = 1; i <= m; i++) {
    long long r = t - i;
    if (r < 4) continue;
    res += COM[n][r] * COM[m][i];
  }
  cout << res << endl;
  return 0;
}
