using System;
using System.Collections.Generic;
using System.Linq;
using System.Globalization;
using System.IO;
using CodeChallenges;
using System.Diagnostics;

#region helpers
namespace CodeChallenges.Boilerplate
{    
    class BufferedStreamReader : StreamReader { const int QUEUE_INITSIZE = 1000; public BufferedStreamReader(String fileName): base(fileName) { } public BufferedStreamReader(Stream stream): base(stream) { } private Queue<string> buffer = new Queue<string>(QUEUE_INITSIZE); public override string ReadLine() { if (buffer.Count > 0) throw new InvalidOperationException("must read from buffer first"); return base.ReadLine(); } public string ReadToken() { while (buffer.Count == 0) { base.ReadLine().Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries).ToList().ForEach((t) => { buffer.Enqueue(t); }); } return buffer.Dequeue(); } public void ResetBuffer() { buffer = new Queue<string>(QUEUE_INITSIZE); } }
    class FormattedStreamWriter : StreamWriter { public FormattedStreamWriter(Stream stream) : base(stream) { } public FormattedStreamWriter(string filePath) : base(filePath) { } public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } } }
    static class IOExtensions
    {
        public static string ReadString(this BufferedStreamReader reader) { return reader.ReadToken(); }
        public static string[] ReadStringArray(this BufferedStreamReader reader, int n) { var array = new string[n]; for (int i = 0; i < n; ++i) { array[i] = reader.ReadToken(); } return array; }
        public static int ReadInt(this BufferedStreamReader reader) { return int.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static int[] ReadIntArray(this BufferedStreamReader reader, int n) { var array = new int[n]; for (int i = 0; i < n; ++i) { array[i] = int.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); } return array; }
        public static uint ReadUnsignedInt(this BufferedStreamReader reader) { return uint.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static long ReadLong(this BufferedStreamReader reader) { return long.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static long[] ReadLongArray(this BufferedStreamReader reader, int n) { var array = new long[n]; for (int i = 0; i < n; ++i) { array[i] = long.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); } return array; }
        public static ulong ReadUnsignedLong(this BufferedStreamReader reader) { return ulong.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static double ReadDouble(this BufferedStreamReader reader) { return double.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static double[] ReadDoubleArray(this BufferedStreamReader reader, int n) { var array = new double[n]; for (int i = 0; i < n; ++i) { array[i] = double.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); } return array; }
        public static decimal ReadDecimal(this BufferedStreamReader reader) { return decimal.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static decimal[] ReadDecimalArray(this BufferedStreamReader reader, int n) { var array = new decimal[n]; for (int i = 0; i < n; ++i) { array[i] = decimal.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); } return array; }
        public static void WriteArrayLine<T>(this FormattedStreamWriter writer, T[] array, int n, string format = "{0}", string separator = " ") { for (int i = 0; i < n; ++i) { if (i > 0) writer.Write(separator); writer.Write(format, array[i]); } writer.WriteLine(); }
        public static void WriteArrayLine<T>(this FormattedStreamWriter writer, T[] array, string format = "{0}", string separator = " ") { writer.WriteArrayLine(array, array.Length, format, separator); }
    }
    abstract class BaseSolver
    {
        public static T[][] Create2DArray<T>(int dim1, int dim2) { var res = new T[dim1][]; for (int i = 0; i < dim1; ++i) res[i] = new T[dim2]; return res; }
        public static T[][][] Create3DArray<T>(int dim1, int dim2, int dim3) { var res = new T[dim1][][]; for (int i = 0; i < dim1; ++i) res[i] = Create2DArray<T>(dim2, dim3); return res; }
        public static T[][][][] Create4DArray<T>(int dim1, int dim2, int dim3, int dim4) { var res = new T[dim1][][][]; for (int i = 0; i < dim1; ++i) res[i] = Create3DArray<T>(dim2, dim3, dim4); return res; }
        public abstract void Do();
    }    
}
#endregion

#region launch
class Program
{
    static void Main(string[] args)
    {
#if SOLVER_ATWORKSPACE
        var run = true; var outputFile = "output.txt"; var inputFile = "input.txt";
        switch (args[0]) { case "g": run = false; outputFile = "input.txt"; inputFile = "output.txt"; break;case "r":default: run = true; inputFile = "input.txt"; outputFile = "output.txt"; break; }
#endif

        using (var writer = new CodeChallenges.Boilerplate.FormattedStreamWriter(
#if SOLVER_ATWORKSPACE
outputFile
#else
            Console.OpenStandardOutput()
#endif
))
        {
            using (var reader = new CodeChallenges.Boilerplate.BufferedStreamReader(
#if SOLVER_ATWORKSPACE
inputFile
#else 
            Console.OpenStandardInput()
#endif
))
            {
#if SOLVER_ATWORKSPACE
                var stopw = new Stopwatch(); stopw.Start();
#endif
#if SOLVER_ATWORKSPACE
                if (run) new ConcreteSolver(reader, writer).Do(); else new Generator(reader, writer).Create();

#else
                new ConcreteSolver(reader, writer).Do();
#endif
#if SOLVER_ATWORKSPACE
                stopw.Stop(); writer.WriteLine("> {0}ms", stopw.ElapsedMilliseconds);
#endif
            }
        }
    }
}
#endregion

namespace CodeChallenges
{
    using CodeChallenges.Boilerplate;

    class ConcreteSolver: BaseSolver
    {
        private readonly BufferedStreamReader reader;
        private readonly FormattedStreamWriter writer;

        public ConcreteSolver(BufferedStreamReader reader, FormattedStreamWriter writer)
        {
            this.reader = reader;
            this.writer = writer;
        }

        public override void Do()
        {
            var a = reader.ReadUnsignedInt();
            var b = reader.ReadUnsignedInt();
            var c = reader.ReadUnsignedInt();
            var x = Math.Max(a, Math.Max(b, c));
            var z = Math.Min(a, Math.Min(b, c));
            var y = a + b + c - x - z;
            int res = 0;
            while (x - z > 1)
            {
                if (x % 2 == 1 || y % 2 == 1 || z % 2 == 1)
                    break;
                ++res;
                var tx = (x + y) / 2;
                var ty = (x + z) / 2;
                var tz = (y + z) / 2;
                x = tx;
                y = ty;
                z = tz;
            }
            if (x % 2 == 0 && y % 2 == 0 && z % 2 == 0)
                writer.WriteLine(-1);
            else
                writer.WriteLine(res);
        }
    }
}

Measured memory_bytes: 11332