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
import math;
su=1
ftab=[1]
for i in range(2,50):
  ftab+=[su];
  su*=i
def c(m,n):
  #print ftab[m],ftab[n-m],ftab[n]
  return ftab[n]/(ftab[m]*ftab[n-m]);



##print ftab
##print "%d"%(ftab[-1])
##print c(4,5)


##print
line=raw_input()
inp=line.split(" ");
n=int(inp[0]);m=int(inp[1]);t=int(inp[2]);
#n,m,t=5,2,5
det=t-5;
boyod=n-4;
girod=m-1;
cnt=0;
for i in range(4,n+1):
  j=t-i;
  if(j<1 or j>m):continue;
##  print i,j,"<";
  
  cnt+=c(i,n)*c(j,m);
##  print c(i,n),c(j,m),c(i,n)*c(j,m);
    


print "%d"%(cnt)

					 	 							 		 		     				