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=list(map(int,input().split()))
comb=[[0 for _ in range(t+1)] for _ in range(n+m+1)]
comb[0][0]=1
comb[1][0]=1
comb[1][1]=1
for i in range(2,len(comb)):
	comb[i][0]=1
	for j in range(1,t+1):
		if i==j:
					comb[i][i]=1
		comb[i][j]=comb[i-1][j]+comb[i-1][j-1]

ans= comb[n+m][t]-(comb[m][t]+n*comb[m][t-1]+ comb[n][2]*comb[m][t-2]+
     comb[n][3]*comb[m][t-3] + comb[n][t])
print(ans)