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
def pascal():
    arr=[[0]*61 for _ in range(61)]
    arr[0][0]=1
    arr[1][0]=arr[1][1]=1
    for i in range(2,61):
        arr[i][0]=1
        for j in range(1,i):
            arr[i][j]=arr[i-1][j-1]+arr[i-1][j]
        arr[i][i]=1
    return arr





b,g,t=map(int,input().split())
pas=pascal()
re=pas[b+g][t]
# print(re)
if(t<=g):
    re-=(pas[g][t]*pas[b][0])
if(t-1<=g):
    re-=(pas[g][t-1]*pas[b][1])
if(t-2<=g):
    re-=(pas[g][t-2]*pas[b][2])
if(t-3<=g):
    re-=(pas[g][t-3]*pas[b][3])
if(t<=b):
    re-=(pas[b][t]*pas[g][0])
print(re)