#include <bits/stdc++.h>   using namespace std;   long long n, ans, val[3001000];   priority_queue<int> q;   int main() {     scanf( %lld , &n);     for (int i = 1; i <= n; i++) scanf( %lld , &val[i]);     for (int i = 1; i <= n; i++) {       q.push(-val[i]);       q.push(-val[i]);       ans += val[i] + q.top();       q.pop();     }     printf( %lld n , ans);     return 0;   }   