/// Brrrr Brrrr
#pragma GCC optimize("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("avx,avx2,fma")

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

#define pb push_back
#define F first
#define S second
#define f(i, a, b)  for(int i = a; i < b; i++)
#define all(a)  a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define sz(x) (int)(x).size()
#define mp(x,y) make_pair(x,y)
#define popCnt(x) (__builtin_popcountll(x))
#define int ll

using ll = long long;
using ii = pair<int, int>;
using ull = unsigned long long;

const int N = 1e5+5, LG = 18, MOD = (119 << 23) + 1;
const long double PI = acos(-1);
const long double EPS = 1e-7;

const int dx[] = {0,0,1,-1};
const int dy[] = {1,-1,0,0};

using vi = vector<int>;
using pii = pair<int, int>;
int mxPrefix[N];
int mxSuffix[N];
int mnPrefix[N];
int mnSuffix[N];
int a[N], n;
void doWork() {

    cin >> n;
    int cur1 = 0, cur2 = 0;
    mxPrefix[0] = LLONG_MIN;
    mnPrefix[0] = LLONG_MAX;
    for(int i = 1; i <= n; i++) {
        cin >> a[i];
        cur1 += a[i];
        cur2 += a[i];
        mxPrefix[i] = max(mxPrefix[i - 1], cur1);
        mnPrefix[i] = min(mnPrefix[i - 1], cur2);
        cur1 = max(cur1, 0ll);
        cur2 = min(cur2, 0ll);
    }

    cur1 = 0, cur2 = 0;
    mxSuffix[n + 1] = LLONG_MIN;
    mnSuffix[n + 1] = LLONG_MAX;
    for(int i = n; i >= 1; --i) {
        cur1 += a[i];
        cur2 += a[i];
        mxSuffix[i] = max(mxSuffix[i + 1], cur1);
        mnSuffix[i] = min(mnSuffix[i + 1], cur2);
        cur1 = max(cur1, 0ll);
        cur2 = min(cur2, 0ll);
    }

    ll ans = 0;
    for(int i = 1; i + 1 <= n; i++) {
        ans = max(ans, mxPrefix[i]-mnSuffix[i+1]);
        ans = max(ans, mxSuffix[i+1]-mnPrefix[i]);
    }

    cout << ans << endl;

}
int32_t main() {
#ifdef ONLINE_JUDGE
    ios_base::sync_with_stdio(0);
    cin.tie(0);
#endif // ONLINE_JUDGE


    int t = 1;
//    cin >> t;
    while (t--) {
        doWork();
    }
    return 0;
}

///Look at my code ya codeomk