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;
inline int _Int() {
  int x;
  scanf("%d", &x);
  return x;
}
long long int bigMod(long long int A, long long int P, int M) {
  long long int R = 1;
  for (A %= M; P; P >>= 1) {
    if (P & 1) R = (R * A) % M;
    A = (A * A) % M;
  }
  return R;
}
const int MOD = 1000000007;
const int M = 2000007;
struct Combinatorics {
  unsigned long long int nCr[31][31];
  long long int fac[M];
  void preCalculations() {
    for (int i = 0; i < 31; i++) {
      for (int j = 0; j < 31; j++) {
        if (j == 0)
          nCr[i][j] = 1;
        else if (i == 0)
          nCr[i][j] = (j == 0);
        else
          nCr[i][j] = nCr[i - 1][j] + nCr[i - 1][j - 1];
      }
    }
    fac[0] = 1;
    for (int i = 1; i < M; i++) {
      fac[i] = (fac[i - 1] * i) % MOD;
    }
  }
  int invFac(int n) { return bigMod(fac[n], MOD - 2, MOD); }
  int nCr_mod(int n, int r) {
    return (((fac[n] * invFac(n - r)) % MOD) * invFac(r)) % MOD;
  }
} _math;
void Main() {
  int n = _Int();
  int m = _Int();
  int k = _Int();
  unsigned long long int Ans = 0;
  for (int B = 4; B <= n; B++) {
    int G = k - B;
    if (G < 1 || G > m) continue;
    Ans += (_math.nCr[n][B] * _math.nCr[m][G]);
  }
  cout << Ans << endl;
}
int main() {
  _math.preCalculations();
  Main();
  return 0;
}
