#include <bits/stdc++.h>
using namespace std;
// type alias
typedef long long LL;
typedef pair<int,int> II;
typedef tuple<int,int,int> III;
typedef vector<int> VI;
typedef vector<string> VS;
typedef unordered_map<int,int> MAPII;
typedef unordered_set<int> SETI;
template<class T> using VV=vector<vector<T>>;
// minmax
template<class T> inline T SMIN(T& a, const T b) { return a=(a>b)?b:a; }
template<class T> inline T SMAX(T& a, const T b) { return a=(a<b)?b:a; }
// repetition
#define FORE(i,a,b) for(int i=(a);i<=(b);++i)
#define REPE(i,n)  for(int i=0;i<=(n);++i)
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  for(int i=0;i<(n);++i)
#define FORR(x,arr) for(auto& x:arr)
#define SZ(a) int((a).size())
// collection
#define ALL(c) (c).begin(),(c).end()
// DP
#define MINUS(dp) memset(dp, -1, sizeof(dp))
#define ZERO(dp) memset(dp, 0, sizeof(dp))
// stdout
#define println(args...) fprintf(stdout, ##args),putchar('\n');
// debug cerr
template<class Iter> void __kumaerrc(Iter begin, Iter end) { for(; begin!=end; ++begin) { cerr<<*begin<<','; } cerr<<endl; }
void __kumaerr(istream_iterator<string> it) { (void)it; cerr<<endl; }
template<typename T, typename... Args> void __kumaerr(istream_iterator<string> it, T a, Args... args) { cerr<<*it<<"="<<a<<", ",__kumaerr(++it, args...); }
template<typename S, typename T> std::ostream& operator<<(std::ostream& _os, const std::pair<S,T>& _p) { return _os<<"{"<<_p.first<<','<<_p.second<<"}"; }
#define __KUMATRACE__ true
#ifdef __KUMATRACE__
#define dump(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); __kumaerr(_it, args); }
#define dumpc(ar) { cerr<<#ar<<": "; FORR(x,(ar)) { cerr << x << ','; } cerr << endl; }
#define dumpC(beg,end) { cerr<<"~"<<#end<<": "; __kumaerrc(beg,end); }
#else
#define dump(args...)
#define dumpc(ar)
#define dumpC(beg,end)
#endif

// $ cp-batch DifferentStrokes | diff DifferentStrokes.out -
// $ g++ -std=c++14 -Wall -O2 -D_GLIBCXX_DEBUG -fsanitize=address DifferentStrokes.cpp && ./a.out

/*
 
 2/4/2019
 
 17:23-17:57 WA
 19:06 give up
 
 It seemed to be hard without greedy approach.
 Sorted by A and B and tried to take max A or max B so far. However it hit WA.
 
 2/5/2019
 
 14:20- read editorials
 
 https://img.atcoder.jp/nikkei2019-qual/editorial.pdf
 https://youtu.be/x5x2Xg_gVWY?t=1872

 I had an idea of formula transformation. However I had no idea how to change it.

 I tried to pick up A and B independently.
 
 */

const int MAX_N=1e6+1;
LL A[MAX_N][2];
int N;

void solve() {
  vector<pair<LL,LL>> X;
  REP(i,N) X.emplace_back(A[i][0],A[i][1]);
  sort(X.rbegin(),X.rend(), [&](pair<LL,LL> a, pair<LL,LL> b) {
    return a.first+a.second<b.first+b.second;
  });
  LL Y[2]={0};
  REP(i,N) Y[i%2]+=(i%2==0?X[i].first:X[i].second);
  cout<<Y[0]-Y[1]<<endl;
}

void solve_wrong() {
  set<pair<LL,int>> Q[2];
  REP(i,N) REP(j,2) Q[j].emplace(A[i][j],i);
  int t=0;
  LL sum[2]={0};
  auto rem=[&](int i) {
//    dump(i);
    REP(t,2) Q[t].erase({A[i][t],i});
  };
  while(SZ(Q[0])||SZ(Q[1])) {
    int tt=t^1;
//    dump(t,tt);
    if(SZ(Q[t])==0) break;
    LL v1=0,v2=0; int i1=-1,i2=-1;
    tie(v1,i1)=*Q[t].rbegin();
    if(SZ(Q[tt])<N) tie(v2,i2)=*Q[tt].rbegin();
    if(i1==i2||i2==-1) {
      sum[t]+=v1,rem(i1);
    } else {
      LL a=v1-v2,b=A[i2][t]-A[i1][tt];
      if(a>=b) sum[t]+=A[i1][t],rem(i1);
      else sum[t]+=A[i2][t],rem(i2);
    }
    t^=1;
  }
  cout<<sum[0]-sum[1]<<endl;
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout<<setprecision(12)<<fixed;
  
  cin>>N;
  REP(i,N) cin>>A[i][0]>>A[i][1];
  solve();
  
  return 0;
}


Measured memory_bytes: 3956