#include <atcoder/all>
#include <bits/stdc++.h>
#ifdef DEBUG
#include "cpp-dump/dump.hpp"
#define dump(...) cpp_dump(__VA_ARGS__)
#else
#define dump(...)
#endif
using namespace std;
using namespace atcoder;
typedef long long ll;
const ll INF = 2 * 1e18;

ll op1 (ll a, ll b) {return max(a,b);}
ll e1() {return -INF;}

void solve() {
    ll n;
    cin >> n;
    vector<ll> A(n);
    for (ll i = 0; i < n; ++i) cin >> A[i];
    vector<ll> t(n+2, -INF);
    // vector<ll> ans(n);

    segtree<ll, op1, e1> segmin(t);
    segtree<ll, op1, e1> segplus(t);
    segmin.set(0, A[0]*(-1));

    if (n == 1) {
        cout << A[0]*(-1) << endl;
        return;
    }
    
    // iにマイナスがかかるときとプラスがかかるときを別に計算する
    for (ll i = 1; i < n; ++i) {
        ll t = segmin.prod(0, i);
        segplus.set(i, A[i]+t);
        t = segplus.prod(0,i);
        // if (t == -INF) continue;
        if (1 == i) {
            segmin.set(i, A[i]*(-1));
        } else {
            segmin.set(i, t + A[i]*(-1));
        }
    }

    ll ans = max(segmin.all_prod(), segplus.all_prod());
    assert(ans != -INF);
    cout << ans << endl;
}

int main() {
    solve();
    return 0;
}