#include <iostream>

using namespace std;

void processVec(int, int*);

int main()
{
    int n;
    
    cin >> n;
    
    int v[n*2 + 1];
    
    for (int i =0; i< n * 2; i++) {
        cin>> v[i];
    }
    
    processVec(n * 2, v);
    
    return 0;
}

void processVec(int n, int *v) {
    
    int middleR = n / 2;
    
    int middleL = middleR - 1;
    
    int count = 0;
    
    while (middleL >= 0 && middleR < n) {
        if(v[middleL] > v[middleR]) {
            count += v[middleL] - v[middleR];
        }
        middleL--;
        middleR++;
        
    }
    
    
    cout<<count;
    
}