#include <bits/stdc++.h> using namespace std; int main() { int n; cin>>n; int a[n]; for(int i = 0;i < n;i++) { cin>>a[i]; } sort(a,a + n); int big = 0; int small = 0; if(n % 2 == 1) { big += a[n - 1]; int sum = 0; for(int i = n - 2;i >= 0;i-=2) { if(sum % 2 == 0) { small += a[i] + a[i - 1]; } else { big += a[i] + a[i - 1]; } sum++; } } else { big += a[n - 1]; small += a[0]; int sum = 0; for(int i = n - 2;i >= 1;i-=2) { if(sum % 2 == 0) { small += a[i] + a[i - 1]; } else { big += a[i] + a[i - 1]; } sum++; } } cout<<abs(big - small)<<endl; return 0; }