#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <list>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <cmath>
#include <utility>
#include <sstream>
#include <queue>
#include <queue>

using namespace std;

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  int64_t best_if_last_pos = 0;
  int64_t best_if_last_neg = -1LL;

  int n;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    int64_t val;
    cin >> val;

    int64_t next_neg = best_if_last_pos - val;
    if (best_if_last_neg != -1 && next_neg < best_if_last_neg) {
      next_neg = best_if_last_neg;
    }

    if (best_if_last_neg != -1) {
      int64_t next_pos = best_if_last_neg + val;
      if (next_pos > best_if_last_pos) {
        best_if_last_pos = next_pos;
      }
    }

    best_if_last_neg = next_neg;
  }

  int64_t ans = best_if_last_pos;
  if (best_if_last_neg != -1LL) {
    ans = max(best_if_last_neg, ans);
  }
  cout << ans << endl;

  return 0;
}