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

#include <atcoder/all>
using namespace atcoder;

using ll = long long;

int main() {
  ll N;
  cin >> N;
  const ll INF = 1LL << 60;
  vector<ll> dp(3, -INF), ep(3);
  dp[2] = 0;
  for(int i = 0; i < N; i++) {
    ll a;
    cin >> a;
    ep[0] = max(dp[0], dp[1] + a);
    ep[1] = max({dp[1], dp[2] - a, dp[0] - a});
    swap(dp, ep);
    // cout << dp[0] << " " << dp[1] << endl;
  }
  cout << max(dp[0], dp[1]) << endl;
}