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
c = [[0 for i in range(102)] for j in range(102)]
c[0][0]=1
for n in range(1,32):
    for k in range(n+1):
        c[n][k]=c[n-1][k-1]+c[n-1][k]

s=raw_input().split()
n=int(s[0])
m=int(s[1])
t=int(s[2])
res=0
for i in range(1,t-3):
    res+=(c[m][i]*c[n][t-i])

print res
