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

int main() {
  int n;
  cin >> n;
  int y[n];
  for ( int i = 0; i < n; i++ ) {
    cin >> y[i];
  }
  if ( n == 1 ) { cout << 0 << endl; return 0; }
  
  long long sum = 0;
  int ch = -1;
  vector<int> v;
  for ( int i = 0; i < n; i++ ) {
    if ( ch == -1 && i != (n-1) && y[i] <= y[i+1] ) { continue; }
    if ( ch == -1 && i == n-1 ) { break; }
    if ( ch == -1 ) {
      ch = y[i];
      v.push_back(y[i]);
    } else if ( i != (n-1) && y[i] < ch ) {
      v.push_back(y[i]);
    } else {
      if ( i == (n-1) && y[i] < ch ) { v.push_back(y[i]); }
      sort(v.begin(), v.end());
      int mid;
      if ( v.size()%2 == 1 ) {
        mid = v[v.size()/2];
        for ( int k = 0; k < v.size(); k++ ) {
          sum += abs(mid-v[k]);
        }
      } else {
        mid = v[(v.size()/2)-1] + v[v.size()/2];
        if ( mid%2 == 0 ) {
          mid /= 2;
          for ( int k = 0; k < v.size(); k++ ) {
            sum += abs(mid-v[k]);
          }
        } else {
          mid /= 2;
          int k;
          for ( k = 0; k < v.size()/2; k++) {
            sum += abs(mid-v[k]);
          }
          mid++;
          for ( ; k < v.size(); k++) {
            sum += abs(mid-v[k]);
          }
        }
      }
      v.clear();
      i--;
      ch = -1;
    }
  }

  cout << sum << endl;
  return 0;
}