import java.io.BufferedReader;
import static java.util.Comparator.*;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.util.AbstractMap;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;

public class Main {
	
//	public static Set<String> mem = new HashSet<String>();
//	public static boolean[] mem_1 = new boolean[100];
//	public static boolean[] mem_2 = new boolean[100];
//	public static Set<Integer> mem = new TreeSet<Integer>();
//	public static Map<String, Integer> mem_1= new HashMap<String, Integer>();
//	public static Map<String, Integer> mem_2 = new HashMap<String, Integer>();
	
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        MyInput in = new MyInput(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        
        Solver solver = new Solver();
        solver.solve(1, in, out);
        
        out.close();
    }
    
    // ======================================================================
    static class Solver {
    	
    	public void solve(int testNumber, MyInput in, PrintWriter out) {
        	long ans = 0;
    		int N = in.nextInt();
    		List<PPP> A = new ArrayList<PPP>();
    		List<PPP> B = new ArrayList<PPP>();
    		boolean[] X = new boolean[N];

    		int a, b;
    		PPP wk = null;
    		for(int i=0; i < N; i++) {
    			a = in.nextInt();
    			b = in.nextInt();
    			wk = new PPP(new Integer(Math.abs(a+b)), new Integer(a), new Integer(b), i);
    			A.add(wk);
    			wk = new PPP(new Integer(Math.abs(b+a)), new Integer(b), new Integer(a), i);
    			B.add(wk);
    		}
    		A.sort(comparing(PPP::getDiff, reverseOrder()).thenComparing(PPP::getVal, reverseOrder()).thenComparing(PPP::getVal_2, reverseOrder()));
    		B.sort(comparing(PPP::getDiff, reverseOrder()).thenComparing(PPP::getVal, reverseOrder()).thenComparing(PPP::getVal_2, reverseOrder()));
    // 		for(int i=0; i < N; i++) {
    // 		    out.println("A : diff = " + A.get(i).getDiff() + "  val = " + A.get(i).getVal() + "  index = " + A.get(i).getKey());
    // 		}
    // 		for(int i=0; i < N; i++) {
    // 		    out.println("B : diff = " + B.get(i).getDiff() + "  val = " + B.get(i).getVal() + "  index = " + B.get(i).getKey());
    // 		}

    		int ia = 0;
    		int ib = 0;
    		int www;
    		for(int i=0; i < N; i++) {
    			if(i % 2 == 0) {
    				while(true) {
     					www = A.get(ia).getKey();
    					if(X[www] == false) {
    						ans += A.get(ia).getVal();
    						X[www] = true;
    						break;
    					}
    					if(ia < N -1)	ia++;
    					else			break;
    				}
    			} else {
    				while(true) {
     					www = B.get(ib).getKey();
    					if(X[www] == false) {
    						ans -= B.get(ib).getVal();
    						X[www] = true;
    						break;
    					}
    					if(ib < N -1)	ib++;
    					else			break;
    				}
    			}
    		}
    		
        	out.println(ans);
        }
    }
    static class PPP {
		Integer diff;
    	Integer val;
    	int key;
    	Integer val_2;
    	
		public PPP(Integer diff, Integer val, Integer val_2, int key) {
			super();
			this.diff = diff;
			this.val = val;
			this.key = key;
			this.val_2 = val_2;
		}
		public Integer getVal() {
			return val;
		}
		public void setVal(Integer val) {
			this.val = val;
		}
		public Integer getDiff() {
			return diff;
		}
		public void setDiff(Integer diff) {
			this.diff = diff;
		}
		public int getKey() {
			return key;
		}
		public void setKey(int key) {
			this.key = key;
		}
		public Integer getVal_2() {
			return val_2;
		}
		public void setVal_2(Integer val_2) {
			this.val_2 = val_2;
		}
    }
    // ======================================================================
    static class Pair<K, V> extends AbstractMap.SimpleEntry<K, V> {
        /** serialVersionUID. */
        private static final long serialVersionUID = 6411527075103472113L;

        public Pair(final K key, final V value) {
            super(key, value);
        }
     }    
    static class MyInput {
        private final BufferedReader in;
        private static int pos;
        private static int readLen;
        private static final char[] buffer = new char[1024 * 8];
        private static char[] str = new char[500 * 8 * 2];
        private static boolean[] isDigit = new boolean[256];
        private static boolean[] isSpace = new boolean[256];
        private static boolean[] isLineSep = new boolean[256];
 
        static {
            for (int i = 0; i < 10; i++) {
                isDigit['0' + i] = true;
            }
            isDigit['-'] = true;
            isSpace[' '] = isSpace['\r'] = isSpace['\n'] = isSpace['\t'] = true;
            isLineSep['\r'] = isLineSep['\n'] = true;
        }
 
        public MyInput(InputStream is) {
            in = new BufferedReader(new InputStreamReader(is));
        }
 
        public int read() {
            if (pos >= readLen) {
                pos = 0;
                try {
                    readLen = in.read(buffer);
                } catch (IOException e) {
                    throw new RuntimeException();
                }
                if (readLen <= 0) {
                    throw new MyInput.EndOfFileRuntimeException();
                }
            }
            return buffer[pos++];
        }
 
        public int nextInt() {
            int len = 0;
            str[len++] = nextChar();
            len = reads(len, isSpace);
            int i = 0;
            int ret = 0;
            if (str[0] == '-') {
                i = 1;
            }
            for (; i < len; i++) ret = ret * 10 + str[i] - '0';
            if (str[0] == '-') {
                ret = -ret;
            }
            return ret;
        }
 
        public String nextString() {
        	String ret = new String(nextDChar()).trim();
            return ret;
        }
 
        public char[] nextDChar() {
            int len = 0;
            len = reads(len, isSpace);
            char[] ret = new char[len + 1];
            for (int i=0; i < len; i++)		ret[i] = str[i];
            ret[len] = 0x00;
            return ret;
        }
 
        public char nextChar() {
            while (true) {
                final int c = read();
                if (!isSpace[c]) {
                    return (char) c;
                }
            }
        }
 
        int reads(int len, boolean[] accept) {
            try {
                while (true) {
                    final int c = read();
                    if (accept[c]) {
                        break;
                    }
                    if (str.length == len) {
                        char[] rep = new char[str.length * 3 / 2];
                        System.arraycopy(str, 0, rep, 0, str.length);
                        str = rep;
                    }
                    str[len++] = (char) c;
                }
            } catch (MyInput.EndOfFileRuntimeException e) {
            }
            return len;
        }
 
        static class EndOfFileRuntimeException extends RuntimeException {
        }
    }
}


Measured memory_bytes: 56776