#include<bits/stdc++.h>
using namespace std;
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);++i)
#define rep(i,n) REP(i,0,n)
int main(){
    int n;
    cin>>n;
    assert(1<=n&&n<=100000);
    int a[n];
    rep(i,n){
        cin>>a[i];
        assert(abs(a[i])<=1000000000);
    }
    sort(a,a+n);
    long long x=0,y=0;
    rep(i,n){
        if(i%2)x+=a[i];
        else y+=a[i];
    }
    cout<<abs(abs(x)-abs(y))<<endl;
    return 0;
}