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(32)] for j in range(32)]
c[0][0]=1
c[1][1]=1
c[1][0]=1
for i in range(2,32):
	c[i][0]=1
	c[i][1]=i
for i in range(2,32):
	for j in range(2,32):
		c[i][j]=c[i-1][j]+c[i-1][j-1]
n,m,t=map(int,raw_input().split())
ans=0
for i in range(4,n+1):
	if t-i>=1 and t-i<=m:
		ans+=(c[n][i]*c[m][t-i])
print ans
