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 java.util.*;
import java.lang.*;
import java.io.*;

public class GFG {
    
    static long[][] pascal = new long[61][61];
    public static void computePascal() 
    { 
    
      
      
    // Iterate through every line and print integer(s) in it 
    for (int line = 0; line < 61; line++) 
    { 
        // Every line has number of integers equal to line number 
        for (int i = 0; i <= line; i++) 
        { 
        // First and last values in every row are 1 
        if (line == i || i == 0) 
            pascal[line][i] = 1; 
        else // Other values are sum of values just above and left of above 
            pascal[line][i] = pascal[line-1][i-1] + pascal[line-1][i]; 
         
        } 
        
    } 
    }
    
	public static void main (String[] args) {

		computePascal();
		Scanner sc = new Scanner(System.in);
		
	
		    int n = sc.nextInt();
		    int m = sc.nextInt();
		    int t = sc.nextInt();
		    long a,b,c,d,e,f;
		    a = pascal[n+m][t];
		    
		    if(t>m)
		    b=0;
		    else
		    b = pascal[n][0] * pascal[m][t];
		    if(t-1>m)
		    c=0;
		    else
		    c = pascal[n][1] * pascal[m][t-1];
		    if(t-2>m)
		    d=0;
		    else
		    d = pascal[n][2] * pascal[m][t-2];
		    if(t-3>m)
		    e=0;
		    else
		    e = pascal[n][3] * pascal[m][t-3];
		    if(t>n)
		    f = 0;
		    else
		    f = pascal[n][t] * pascal[m][0];
		    System.out.println(a-(b+c+d+e+f));
		}
	}
