Jzzhu has a big rectangular chocolate bar that consists of n × m unit squares. He wants to cut this bar exactly k times. Each cut must meet the following requirements:

  * each cut should be straight (horizontal or vertical); 
  * each cut should go along edges of unit squares (it is prohibited to divide any unit chocolate square with cut); 
  * each cut should go inside the whole chocolate bar, and all cuts must be distinct. 



The picture below shows a possible way to cut a 5 × 6 chocolate for 5 times.

<image>

Imagine Jzzhu have made k cuts and the big chocolate is splitted into several pieces. Consider the smallest (by area) piece of the chocolate, Jzzhu wants this piece to be as large as possible. What is the maximum possible area of smallest piece he can get with exactly k cuts? The area of a chocolate piece is the number of unit squares in it.

Input

A single line contains three integers n, m, k (1 ≤ n, m ≤ 109; 1 ≤ k ≤ 2·109).

Output

Output a single integer representing the answer. If it is impossible to cut the big chocolate k times, print -1.

Examples

Input

3 4 1


Output

6


Input

6 4 2


Output

8


Input

2 3 4


Output

-1

Note

In the first sample, Jzzhu can cut the chocolate following the picture below:

<image>

In the second sample the optimal division looks like this:

<image>

In the third sample, it's impossible to cut a 2 × 3 chocolate 4 times.
import java.io.*;
import java.util.*;

public class C implements Runnable {
	FastReader sc;
	PrintWriter out;
	long mod = (long)1e9 + 7;

	/*
	 x1+x2+x3 = k
	 |x1-x2| = d1
	 |x2-x3| = d2
	 
	 2*x1 + x3 = d1+k
	 x1 - x3 = d1+d2
	 
	 x1 = (2*d1+d2+k)/3
	 
	 */
	
	void solve() 
	{	
		int tc = 1;
		outer: while(tc-- > 0)
		{
			long n = sc.nl();
			long m = sc.nl();
			long k = sc.nl();
			
			long ans = -1L;
			for(long cx = 1; cx <= n; cx++)
			{
				long smallestPiece = n/cx;
				
				long largestX = n/smallestPiece;
				//System.out.println(cx+" "+smallestPiece+" "+largestX);
				cx = largestX;
				
				smallestPiece = n/cx;
				long otherPiece = 0L;
				if(k-cx+2 == 0)
				{
					smallestPiece = n/(cx-1);
					otherPiece = m/(k-cx+3);
				}
				else
				{
					otherPiece = m/(k-cx+2);
				}
				
				ans = Math.max(ans,smallestPiece*otherPiece);
			
			}
			for(long cy = 1; cy <= m; cy++)
			{
				long smallestPiece = m/cy;
				
				long largestX = m/smallestPiece;
				//System.out.println(cy+" "+smallestPiece+" "+largestX);
				cy = largestX;
				
				smallestPiece = m/cy;
				long otherPiece = 0L;
				if(k-cy+2 == 0)
				{
					smallestPiece = m/(cy-1);
					otherPiece = n/(k-cy+3);
				}
				else
				{
					otherPiece = n/(k-cy+2);
				}
				
				ans = Math.max(ans,smallestPiece*otherPiece);
			
			}
			if(ans == 0 || ans == -1)
			out.println(-1);
			
			else out.println(ans);
		}
	}
	
	class Pair implements Comparable<Pair>
	{
		
		int x;
		int y;
		
		Pair(int x,int y)
		{
			this.x = x;
			this.y = y;
		}
		
		public int compareTo(Pair o) 
		{
			
			if(x != o.x)
			{
				if(x > o.x) return 1;  //increasing order
				else return -1;	
			}
			else
			{
				if(y > o.y) return 1;  //increasing order
				else return -1;	
			}
		}
	}

	public void run() 
	{
		out = new PrintWriter(System.out);
		sc = new FastReader();
		solve();
		out.flush();
	}

	public static void main(String[] args) 
	{
		new Thread(null, new C(), "Main", 1 << 28).start();
	}

	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 ni() 
        { 
            return Integer.parseInt(next()); 
        } 
  
        long nl() 
        { 
            return Long.parseLong(next()); 
        } 
  
        double nd() 
        { 
            return Double.parseDouble(next()); 
        } 
  
        String nln() 
        { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
        

		int[] nia(int n) {
			int[] ar = new int[n];
			for (int i = 0; i < n; i++)
				ar[i] = ni();
			return ar;
		}
		
		long[] nla(int n) {
			long[] ar = new long[n];
			for (int i = 0; i < n; i++)
				ar[i] = nl();
			return ar;
		}

	    
		int[][] nim(int n, int m) {
			int[][] ar = new int[n][];
			for (int i = 0; i < n; i++) {
				ar[i] = nia(m);
			}
			return ar;
		}

		long[][] nlm(int n, int m) {
			long[][] ar = new long[n][];
			for (int i = 0; i < n; i++) {
				ar[i] = nla(m);
			}
			return ar;
		}
		
		String reverse(String s)
		{
			StringBuilder r = new StringBuilder(s);
			return r.reverse().toString();
		}
		
		void merge1(int arr[], int l, int m, int r)
	    {
	        int n1 = m - l + 1;
	        int n2 = r - m;
	        int L[] = new int [n1];
	        int R[] = new int [n2];
	        for (int i=0; i<n1; ++i)
	            L[i] = arr[l + i];
	        for (int j=0; j<n2; ++j)
	            R[j] = arr[m + 1+ j];
	        int i = 0, j = 0;
	        int k = l;
	        while (i < n1 && j < n2)
	        {
	            if (L[i]<=R[j])
	            {
	                arr[k] = L[i];
	                i++;
	            }
	            else
	            {
	                arr[k] = R[j];
	                j++;
	            }
	            k++;
	        }
	        while (i < n1)
	        {
	            arr[k] = L[i];
	            i++;
	            k++;
	        }
	        while (j < n2)
	        {
	            arr[k] = R[j];
	            j++;
	            k++;
	        }
	    }
	    void sort1(int arr[], int l, int r)
	    {
	        if (l < r)
	        {
	            int m = (l+r)/2;
	            sort1(arr, l, m);
	            sort1(arr , m+1, r);
	            merge1(arr, l, m, r);
	        }
	    }
    }
}