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
var c = {};
function T(i, n) {
  if (i > n / 2) i = n - i;
  if (i === 0) return 1;
  if (c[i + '+' + n]) return c[i + '+' + n];
  if (i == 1) {
    return n;
  }
  var ans = 0;
  for (var j = 1; j < n; j++) {
    ans += T(i - 1, j);
  }
  return c[i + '+' + n] = ans;
}
 
const MAX = Math.pow(2,53)-5;
print(function(n, m, t) {
 
  var a = [];
 
  for (var i = 1; i <= m; i++) {
    var j = t - i;
    if (j <= n && j >= 4) {
      var x = T(i, m);
      var y = T(j, n);
      if(x*y>MAX){
        x.toString().split('').map(Number).reverse().forEach(function(v, i){
          a.push(x*v*Math.pow(10, i));
        });
      }else{
        a.push(x*y);
      }
    }
  }
 
  return a.map(function(v){
    return v.toString().split('').map(Number);
  }).reduce(function(a,b){
    var sum=[];
    var c=0;
    for(i=a.length-1, j=b.length-1; i>=0||j>=0; i--,j--){
      var v = (a[i]||0) +  (b[j]||0) + c;
      c=Math.floor(v/10);
      sum.push(v%10);
    }
    if(c>0){
      sum.push(c);
    }
    return sum.reverse();
  }).join('');
 
}.apply(0, readline().split(' ').map(Number)));