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.Scanner;
import java.math.*;
import java.io.*;
public class Main
{
    
    public static void main(String[] args)
    {
        
        int n,m,t;
        Scanner s = new Scanner(System.in);
        BigInteger ans,b,a1,a2,a3;
        
        // for(int i=0;i<=65;i++){
                
        // }
        
        
        while(s.hasNext()){
            ans=BigInteger.ZERO;
            n=s.nextInt();
            m=s.nextInt();
            t=s.nextInt();
            for(int i=4;i<t;i++){
                //ans=ans.add()
                //in[n]/(in[n-i]*in[i])
                if(i>n||t-i>m) continue;
                
                if(i<n){
                    a1=new BigInteger(in[n]);
                    a2=new BigInteger(in[n-i]);
                    a3=new BigInteger(in[i]);
                    a1=a1.divide(a2.multiply(a3));
                
                }else{
                    a1=BigInteger.ONE;
                }
                
                if(t-i<m){
                    a1=a1.multiply(new BigInteger(in[m]));
                    a2=new BigInteger(in[t-i]);
                    a3=new BigInteger(in[m-t+i]);
                    a1=a1.divide(a2.multiply(a3));
                }
                   
                ans=ans.add(a1);
            }
            System.out.println(ans);
        }
        
        
    }

    static String[] in={
        "1",
        "1",
        "2",
        "6",
        "24",
        "120",
        "720",
        "5040",
        "40320",
        "362880",
        "3628800",
        "39916800",
        "479001600",
        "6227020800",
        "87178291200",
        "1307674368000",
        "20922789888000",
        "355687428096000",
        "6402373705728000",
        "121645100408832000",
        "2432902008176640000",
        "51090942171709440000",
        "1124000727777607680000",
        "25852016738884976640000",
        "620448401733239439360000",
        "15511210043330985984000000",
        "403291461126605635584000000",
        "10888869450418352160768000000",
        "304888344611713860501504000000",
        "8841761993739701954543616000000",
        "265252859812191058636308480000000",
        "8222838654177922817725562880000000",
        "263130836933693530167218012160000000",
        "8683317618811886495518194401280000000",
        "295232799039604140847618609643520000000",
        "10333147966386144929666651337523200000000",
        "371993326789901217467999448150835200000000",
        "13763753091226345046315979581580902400000000",
        "523022617466601111760007224100074291200000000",
        "20397882081197443358640281739902897356800000000",
        "815915283247897734345611269596115894272000000000",
        "33452526613163807108170062053440751665152000000000",
        "1405006117752879898543142606244511569936384000000000",
        "60415263063373835637355132068513997507264512000000000",
        "2658271574788448768043625811014615890319638528000000000",
        "119622220865480194561963161495657715064383733760000000000",
        "5502622159812088949850305428800254892961651752960000000000",
        "258623241511168180642964355153611979969197632389120000000000",
        "12413915592536072670862289047373375038521486354677760000000000",
        "608281864034267560872252163321295376887552831379210240000000000",
        "30414093201713378043612608166064768844377641568960512000000000000",
        "1551118753287382280224243016469303211063259720016986112000000000000",
        "80658175170943878571660636856403766975289505440883277824000000000000",
        "4274883284060025564298013753389399649690343788366813724672000000000000",
        "230843697339241380472092742683027581083278564571807941132288000000000000",
        "12696403353658275925965100847566516959580321051449436762275840000000000000",
        "710998587804863451854045647463724949736497978881168458687447040000000000000",
        "40526919504877216755680601905432322134980384796226602145184481280000000000000",
        "2350561331282878571829474910515074683828862318181142924420699914240000000000000",
        "138683118545689835737939019720389406345902876772687432540821294940160000000000000",
        "8320987112741390144276341183223364380754172606361245952449277696409600000000000000",
        "507580213877224798800856812176625227226004528988036003099405939480985600000000000000",
        "31469973260387937525653122354950764088012280797258232192163168247821107200000000000000",
        "1982608315404440064116146708361898137544773690227268628106279599612729753600000000000000",
        "126886932185884164103433389335161480802865516174545192198801894375214704230400000000000000",
        "8247650592082470666723170306785496252186258551345437492922123134388955774976000000000000000",
    };

}

 	  	 	   					   	 					