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
n,m,t1 = list(int(x) for x in raw_input().split())
ans,fact = 0,[]
fact.append(1)
for i in xrange(1,31) : fact.append(i*fact[i-1]);
for j in xrange(4,n+1):
    cnt,t = 0,(t1-j)
    if(t<=0) : break;
    if(t>m) : continue;
    k = fact[m-t]*fact[t];
    cnt = (fact[m]/k);
    k = fact[n-j]*fact[j];
    cnt*=(fact[n]/k);
    ans+=cnt;
print int(ans);

