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
'''input
20 20 40
'''	
fact=[1]*61
for i in range(1,61):
	fact[i]=fact[i-1]*i
def ncr(n,r):
	return (fact[n]//(fact[n-r]*fact[r]))
b,g,t=map(int,input().strip().split(' '))
ans=0
for i in range(4,t):
	#print(i,t-i,ncr(b,i),ncr(g,t-i))
	ans+=(ncr(b,i)*ncr(g,t-i))
print(ans)