#include<bits/stdc++.h>
using namespace std;

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int n;
	cin >> n;
	vector<int> p(n);
	for(int i = 0; i < n; ++i){
		cin >> p[i];
	}
	long long ans = 0;
	priority_queue<pair<int,int>> pq;
	for(int i = n-1; i >= 0; --i){
		if(pq.empty()) pq.push({p[i],-1});
		else {
			if(pq.top().first > p[i]) {
				auto x = pq.top();
				pq.pop();
				ans += x.first  - p[i];
				if(x.second != -1) {
					pq.push({x.first, -1});
				}
				pq.push({p[i],1});
			}
			else {
				pq.push({p[i],-1});
			}
		}
	}
	cout << ans << endl;
}