import javax.xml.crypto.Data;
import java.io.*;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        InputReader sc = new InputReader(System.in);
        PrintWriter pw = new PrintWriter(System.out);
        Random gen = new Random();
        int test = 1;//sc.nextInt();
        while(test-->0) {

            int [] ar = new int[3];
            int e = 0;
            int o = 0;
            int ans = 0;
            for(int i=0;i<3;i++)
            {
                ar[i]=sc.nextInt();
                if(ar[i]%2==0)
                    e++;
                else
                    o++;
            }
            Arrays.sort(ar);
            if(e==0 || o==0)
            {
                ans = (ar[2]-ar[1])/2 + (ar[2]-ar[0])/2 ;
            }
            else
            {
                if(e==2)
                {
                    if(ar[0]%2==0)
                        ar[0]++;
                    if(ar[1]%2==0)
                        ar[1]++;
                    if(ar[2]%2==0)
                        ar[2]++;

                    ans++;

                    Arrays.sort(ar);

                    ans += (ar[2]-ar[1])/2 + (ar[2]-ar[0])/2;

                }
                else
                {
                    if(ar[0]%2!=0)
                        ar[0]++;
                    if(ar[1]%2!=0)
                        ar[1]++;
                    if(ar[2]%2!=0)
                        ar[2]++;

                    ans++;
                    Arrays.sort(ar);
                    ans += (ar[2]-ar[1])/2 + (ar[2]-ar[0])/2;
                }
            }
            pw.println(ans);
        }
        pw.close();

    }




















































































































































































    static class Data implements Comparable<Data>{
        int x, a;

        public Data (int m, int n) {
            x = m;
            a = n;
        }
        @Override
        public int compareTo(Data o) {
            return a - o.a;
        }
    }


    static class InputReader {

        private final InputStream stream;
        private final byte[] buf = new byte[8192];
        private int curChar, snumChars;

        public InputReader(InputStream st) {
            this.stream = st;
        }

        public int read() {
            if (snumChars == -1)
                throw new InputMismatchException();
            if (curChar >= snumChars) {
                curChar = 0;
                try {
                    snumChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (snumChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public int[] nextIntArray(int n) {
            int [] a = new int[n];
            for (int i = 0; i < n; i++) {
                a[i] = nextInt();
            }
            return a;
        }

        public static int[] shuffle(int[] a, Random gen)
        { for(int i = 0, n = a.length;i < n;i++)
        { int ind = gen.nextInt(n-i)+i;
            int d = a[i];
            a[i] = a[ind];
            a[ind] = d;

        }
            return a;
        }


        public String readString() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public String nextLine() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isEndOfLine(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        private boolean isEndOfLine(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }

    }

}


Measured memory_bytes: 32628