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.io.*;
import java.math.*;
public class Class{

    static long[][] dp = new long[61][61];
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        int n = Integer.parseInt(st.nextToken());
        int m = Integer.parseInt(st.nextToken());
        int t = Integer.parseInt(st.nextToken());
        
        for(int i=0; i<=60; i++)dp[i][0] = 1;
        for(int i=1; i<=60; i++)
            for(int j=1; j<=i; j++)dp[i][j] = dp[i-1][j-1]+dp[i-1][j];
        System.out.print(dp[n+m][t]-dp[n][0]*dp[m][t]-dp[n][1]*dp[m][t-1]-dp[n][2]*dp[m][t-2]-dp[n][3]*dp[m][t-3]-dp[n][t]*dp[m][0]);

    }   
        
    static class Pair{
        long start;
        long end;
        
        public Pair(long start, long end){
            this.start = start;
            this.end = end;
        }
        
        public int hashCode() {
            return (int)(this.start + this.end);
        }
        
        public boolean equals(Object p){
            if(((Pair)p).start==this.start && ((Pair)p).end==this.end)return true;
            return false;
        }
        
        public String toString(){
            return this.start+" "+this.end;
        }
    }
}