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,t=raw_input().split()
n=int(n);
m=int(m);
t=int(t);
def getS( c,n):
    sum=1;
    for i in range(0,c):
        sum=sum*(n-i);
    for i in range(1,c+1):
        sum=sum/i;
    return sum;
j=t-4;
ans=0;
for i in range(4,n+1):
    ans=ans+getS(i,n)*getS(j,m);
    j-=1;
    if j==0:
        break;
print("%d" % ans);