using System;

public class Program
{
    private int N;
    int[] A, B;

    public void Solve()
    {
        var sc = new Scanner();

        N = sc.NextInt();
        A = new int[N];
        B = new int[N];
        for (int i = 0; i < N; i++)
        {
            A[i] = sc.NextInt();
            B[i] = sc.NextInt();
        }

        int[] arT = new int[N];
        int[] arA = new int[N];
        for (int i = 0; i < N; i++)
        {
            arT[i] = i;
            arA[i] = i;
        }

        // 高橋くんがi取る　高橋くんがA[i]得して　青木くんがB[i]損する

        Array.Sort(arT, (a, b) =>
        {
            if (A[a] + B[a] == A[b] + B[b])
            {
                return -A[a].CompareTo(A[b]);
            }
            else
            {
                return -(A[a] + B[a]).CompareTo(A[b] + B[b]);
            }
        });

        Array.Sort(arA, (a, b) =>
        {
            if (A[a] + B[a] == A[b] + B[b])
            {
                return -B[a].CompareTo(B[b]);
            }
            else
            {
                return -(A[a] + B[a]).CompareTo(A[b] + B[b]);
            }
        });

        long takahashi = 0;
        long aoki = 0;

        bool[] Used = new bool[N];

        int tIndex = 0;
        int aIndex = 0;

        for (int i = 0; i < N; i++)
        {
            if (i % 2 == 0)
            {
                for (; tIndex < N; tIndex++)
                {
                    if(!Used[arT[tIndex]])break;
                }

                takahashi += A[arT[tIndex]];
                Used[arT[tIndex]] = true;
            }
            else
            {
                for (; aIndex < N; aIndex++)
                {
                    if (!Used[arA[aIndex]]) break;
                }

                aoki += B[arA[aIndex]];

                Used[arA[aIndex]] = true;
            }
        }

        Console.WriteLine(takahashi - aoki);
    }


    public static void Main(string[] args)
    {
        new Program().Solve();
    }
}

class Scanner
{
    public Scanner()
    {
        _pos = 0;
        _line = new string[0];
    }

    const char Separator = ' ';
    private int _pos;
    private string[] _line;

    #region スペース区切りで取得

    public string Next()
    {
        if (_pos >= _line.Length)
        {
            _line = Console.ReadLine().Split(Separator);
            _pos = 0;
        }

        return _line[_pos++];
    }

    public int NextInt()
    {
        return int.Parse(Next());
    }

    public long NextLong()
    {
        return long.Parse(Next());
    }

    public double NextDouble()
    {
        return double.Parse(Next());
    }

    #endregion

    #region 型変換

    private int[] ToIntArray(string[] array)
    {
        var result = new int[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = int.Parse(array[i]);
        }

        return result;
    }

    private long[] ToLongArray(string[] array)
    {
        var result = new long[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = long.Parse(array[i]);
        }

        return result;
    }

    private double[] ToDoubleArray(string[] array)
    {
        var result = new double[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = double.Parse(array[i]);
        }

        return result;
    }

    #endregion

    #region 配列取得

    public string[] Array()
    {
        if (_pos >= _line.Length)
            _line = Console.ReadLine().Split(Separator);

        _pos = _line.Length;
        return _line;
    }

    public int[] IntArray()
    {
        return ToIntArray(Array());
    }

    public long[] LongArray()
    {
        return ToLongArray(Array());
    }

    public double[] DoubleArray()
    {
        return ToDoubleArray(Array());
    }

    #endregion
}

Measured memory_bytes: 18880