#include <stdio.h>
#include <string.h>

int main(void) {
    int i, n, l, r;
    int a[200000];
    long long ans;

    scanf("%d", &n);

    for (i = 0; i < 2 * n; ++i) scanf("%d", &a[i]);

    l = 0, r = 2 * n - 1;
    ans = 0;

    while (r - l >= 0) {
        if (a[l] - a[l+1] > a[r] - a[r-1]) {
            ans += a[l] - a[l+1];
            l += 2;
        } else {
            ans += a[r] - a[r-1];
            r -= 2;
        }
    }

    printf("%lld\n", ans);
}