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.io.*;
import java.math.BigInteger;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public class Contest {
	
	
	
	
	public static int gcd(int n1, int n2)
    {
        if (n2 != 0)
            return gcd(n2, n1 % n2);
        else
            return n1;
    }
	
//////////////////	
	
	
	static class pair {
        Integer x,y;
        pair (int x,int y){
            this.x=x;
            this.y=y;
        }
    }
	
//////////////////	
	
	static class length implements Comparator<String>
	{
		public int compare(String a,String b)
		{
			return(a.length()-b.length());
		}
	}
	
	
//////////////////
	
	
	
	
	
	   static class FastReader
	   {
		   BufferedReader br;
		   StringTokenizer st;
		   public FastReader()
		   {
			   br = new BufferedReader(new InputStreamReader(System.in));
		   }
		   
		   
		   String next() 
	        { 
	            while (st == null || !st.hasMoreElements()) 
	            { 
	                try
	                { 
	                    st = new StringTokenizer(br.readLine()); 
	                } 
	                catch (IOException  e) 
	                { 
	                    e.printStackTrace(); 
	                } 
	            } 
	            return st.nextToken(); 
	        } 
		   
		   
		   int nextInt()
		   {
			   return Integer.parseInt(next());
		   }
		   long nextLong()
		   {
			   return Long.parseLong(next());
		   }
		   double nextDouble() 
	        { 
	            return Double.parseDouble(next()); 
	        } 
		   
		   String nextLine() 
	        { 
	            String str = ""; 
	            try
	            { 
	                str = br.readLine(); 
	            } 
	            catch (IOException e) 
	            { 
	                e.printStackTrace(); 
	            } 
	            return str; 
	        } 
	   }
	   
////////////////////// 
	   
	  public static long Divisors(long n) 
	   { 
	       // Note that this loop runs till square root 
		   long sum=0;
	       for (int i=1; i*i<=(n); i++) 
	       { 
	           if (n%i == 0) 
	           { 
	               // If divisors are equal, print only one 
	               if (n/i == i) 
	               {
	                  // printf("%d ", i); 
	            	   sum=sum+1;
	               }
	     
	               else // Otherwise print both 
	               {
	                   //printf("%d %d ", i, n/i); 
	            	   sum=sum+2;
	               }
	           } 
	       } 
	       return(sum);
	   } 
	   
/////////////////////	  
	  
	  public static long SmallestPrimeDivisor(long n) 
	  { 
	      // if divisible by 2 
	      if (n % 2 == 0) 
	          return 2; 
	    
	      // iterate from 3 to sqrt(n) 
	      for (long i = 3; i * i <= n; i += 2) { 
	          if (n % i == 0) 
	              return i; 
	      } 
	    
	      return n; 
	  } 
	    
////////////////////	  
	   
	   public static boolean isprime(long n)
	    {
	        int count=0;
	     
	        for(long i=2;i*i<=n;i++)
	        {
	            if(n%i==0)
	            {
	                return(false);
	            }
	        }
	        return(true);
	    }
	
	   
//////////////////////
	   
	     //   (x^n)%1000000007
	   public static long modularExponentiation(long x,long n,long M)
	   {
	       if(n==0)
	           return 1;
	       else if(n%2 == 0)        //n is even
	           return modularExponentiation((x*x)%M,n/2,M);
	       else                             //n is odd
	           return (x*modularExponentiation((x*x)%M,(n-1)/2,M))%M;

	   }
	   
	   public static long nCr(int n,int k)
	   {
		  if(k==0)
			  return 1;
		  return(n*nCr(n-1,k-1)/k);
	   }
	   
	 
	   
	   

		public static void main(String []args) throws Exception
		{
			
			
			 FastReader in =new FastReader();	
			 PrintWriter pw = new PrintWriter(System.out);
			 int n=in.nextInt();
			 int m=in.nextInt();
			 int t=in.nextInt();
			 int i=1;
			 int j=t-1;
			 long ans=0;
			 while(j>=4)
			 {
				 ans+=(nCr(m,i)*nCr(n,j));
				 i++;
				 j=t-i;
			 }
			 pw.println(ans);
			
			
	
	        pw.flush();
			pw.close();
			
			
			
			
	}
		
		
}		
		
		
		
		
		
		
		
	

