#include<iostream>
#include<algorithm>
using namespace std;

#define ll long long

const int MAXN = 100005;
struct node{
    int a, b;
}p[MAXN], q[MAXN];
int n, tot1 = 0, tot2 = 0;

bool cmp1(node x, node y){
    return x.a > y.a;
}
bool cmp2(node x, node y){
    return x.b < y.b;
}

int main(){
    freopen("nit.in", "r", stdin);
    freopen("nit.out", "w", stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n;
    for(int i = 1;i <= n;i ++){
        int x, y; cin >> x >> y;
        if(x >= y) p[++ tot1].a = x, p[tot1].b = y;
        else q[++ tot2].a = x, q[tot2].b = y;
    }
    sort(p + 1, p + tot1 + 1, cmp1);
    sort(q + 1, q + tot2 + 1, cmp2);
    ll A = 0, B = 0;
    bool flag = 1;
    for(int i = 1;i <= tot1;i ++){
        if(flag){
            A += p[i].a;
            B += p[i].b;
        }
        else{
            B += p[i].a;
            A += p[i].b;
        }
        flag = !flag;
    }
    flag = 1;
    for(int i = 1;i <= tot2;i ++){
        A += q[i].a;
        B += q[i].b;
    }
    cout << A - B << '\n';
    return 0;
}