#include <bits/stdc++.h>
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using std::cin;
using std::cout;
using std::lower_bound;
using std::string;
using std::upper_bound;
using std::vector;
using vi = vector<long long>;
using vii = vector<vi>;
using pii = std::pair<long long, long long>;
constexpr long long MOD = 1e9 + 7;
constexpr long long MAX = 3e6;
constexpr long long inf = (1ll << 60);
template <class T>
class prique : public std::priority_queue<T, std::vector<T>, std::greater<T>> {
};
template <typename T>
struct Segment_tree {
  long long N;
  T mem;
  vector<T> node;
  Segment_tree(vector<T> &X, T m) : mem(m) {
    long long sz = X.size();
    N = 1;
    while (N < sz) N *= 2;
    node.resize(2 * N - 1, mem);
    for (long long i = (long long)(0); i < (long long)(sz); i++)
      node[N - 1 + i] = X[i];
    for (long long i = (long long)(N - 2); (long long)(0) <= i; i--) {
      node[i] = Compare(node[i * 2 + 1], node[i * 2 + 2]);
    }
  }
  T Compare(T &A, T &B) { return std::max(A, B); }
  void update(long long X, T val) {
    X += N - 1;
    node[X] = val;
    while (X > 0) {
      X = (X - 1) / 2;
      node[X] = Compare(node[X * 2 + 1], node[X * 2 + 2]);
    }
  }
  T Query(long long a, long long b, long long now, long long l, long long r) {
    if (r < 0) r = N;
    if (r <= a || b <= l) return mem;
    if (a <= l && r <= b) return node[now];
    auto vl = Query(a, b, now * 2 + 1, l, (l + r) / 2),
         vr = Query(a, b, now * 2 + 2, (l + r) / 2, r);
    return Compare(vl, vr);
  }
};
template <typename T>
struct lazy_Segment_tree {
  int N;
  vector<T> node, lazy;
  T INF;
  lazy_Segment_tree(vector<T> X, T Y) : INF(Y) {
    N = 1;
    while (X.size() > N) N *= 2;
    node.resize(2 * N - 1, Y);
    lazy.resize(2 * N - 1);
    for (long long i = (long long)(0); i < (long long)(X.size()); i++)
      node[i + N - 1] = X[i];
    for (long long i = (long long)(N - 2); (long long)(0) <= i; i--)
      node[i] = compare(node[i * 2 + 1], node[i * 2 + 2]);
  }
  T compare(T X, T Y) { return std::max(X, Y); }
  T plus(T X, int l, int r) { return X; }
  void eval(int now, int l, int r) {
    if (lazy[now] == 0) return;
    node[now] += lazy[now];
    if (r - l > 1) {
      lazy[now * 2 + 1] += plus(lazy[now], l, r);
      lazy[now * 2 + 2] += plus(lazy[now], l, r);
    }
    lazy[now] = 0;
  }
  void update(int a, int b, T add, int now = 0, int l = 0, int r = -1) {
    if (r < 0) r = N;
    eval(now, l, r);
    if (b <= l || r <= a) return;
    if (a <= l && r <= b) {
      lazy[now] += add;
      eval(now, l, r);
    } else {
      update(a, b, add, now * 2 + 1, l, (r + l) / 2);
      update(a, b, add, now * 2 + 2, (r + l) / 2, r);
      node[now] = compare(node[now * 2 + 1], node[now * 2 + 2]);
    }
  }
  T Query(int a, int b, int now = 0, int l = 0, int r = -1) {
    if (r < 0) r = N;
    eval(now, l, r);
    if (b <= l || r <= a) return INF;
    if (a <= l && r <= b) return node[now];
    return compare(Query(a, b, now * 2 + 1, l, (r + l) / 2),
                   Query(a, b, now * 2 + 2, (r + l) / 2, r));
  }
};
struct Tree {
  int N;
  vii dp;
  vi dist;
  Tree(vii edge) {
    N = edge.size();
    dp.resize(N);
    dist.resize(N, -1);
    for (int i = 0; i < N; i++) dp[i].resize(30);
    dist[0] = dp[0][0] = 0;
    std::queue<int> que;
    que.push(0);
    while (!que.empty()) {
      int now = que.front();
      que.pop();
      for (int i = 0; i < edge[now].size(); i++) {
        int next = edge[now][i];
        if (dist[next] == -1) {
          dist[next] = dist[now] + 1;
          que.push(next);
          dp[next][0] = now;
        }
      }
    }
    for (int i = 1; i < 30; i++) {
      for (int j = 0; j < N; j++) dp[j][i] = dp[dp[j][i - 1]][i - 1];
    }
  }
  int LCA(int X, int Y) {
    if (dist[X] < dist[Y]) std::swap(X, Y);
    {
      int Z = dist[X] - dist[Y];
      for (int i = 0; i < 30; i++) {
        if (Z & (1 << i)) {
          X = dp[X][i];
        }
      }
    }
    if (X == Y) return X;
    for (int i = 29; i >= 0; i--) {
      if (dp[X][i] != dp[Y][i]) {
        X = dp[X][i];
        Y = dp[Y][i];
      }
    }
    return dp[X][0];
  }
};
struct Binary_indexed_tree {
  int N;
  vi bit;
  Binary_indexed_tree(int n) : N(n) { bit.resize(N + 1, 0); }
  void add(int x, long long a) {
    for (x; x <= N; x += (x & -x)) bit[x] += a;
  }
  long long sum(int x) {
    long long ret = 0;
    for (x; x > 0; x -= (x & -x)) ret += bit[x];
    return ret;
  }
  long long lower_bound(long long X) {
    if (sum(N) < X) return -1;
    long long ret = 0, memo = 1, sum = 0;
    while (memo * 2 <= N) memo *= 2;
    while (memo > 0) {
      if (memo + ret <= N && sum + bit[memo + ret] < X) {
        sum += bit[memo + ret];
        ret += memo;
      }
      memo /= 2;
    }
    return ret + 1;
  }
};
struct Union_Find {
  long long N;
  vi par;
  vi siz;
  Union_Find(int n) : N(n) {
    par.resize(N);
    siz.resize(N, 1);
    for (long long i = (long long)(0); i < (long long)(N); i++) par[i] = i;
  }
  long long root(long long X) {
    if (par[X] == X) return X;
    return par[X] = root(par[X]);
  }
  bool same(long long X, long long Y) { return root(X) == root(Y); }
  void unite(long long X, long long Y) {
    X = root(X);
    Y = root(Y);
    if (X == Y) return;
    par[X] = Y;
    siz[Y] += siz[X];
    siz[X] = 0;
  }
  long long size(long long X) { return siz[root(X)]; }
};
long long modpow(long long a, long long n, long long mod) {
  long long res = 1;
  while (n > 0) {
    if (n & 1) res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
vi fac, finv, inv;
void COMinit() {
  fac.resize(MAX);
  finv.resize(MAX);
  inv.resize(MAX);
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}
long long COM(long long n, long long r) {
  if (n < r || n < 0 || r < 0) return 0;
  return fac[n] * finv[r] % MOD * finv[n - r] % MOD;
}
void comp(vi &A) {
  std::map<long long, long long> memo;
  for (long long i = (long long)(0); i < (long long)(A.size()); i++)
    memo[A[i]] = 0;
  long long cnt = 1;
  for (auto &p : memo) p.second = cnt++;
  for (long long i = (long long)(0); i < (long long)(A.size()); i++)
    A[i] = memo[A[i]];
}
void dec(std::map<long long, long long> &mem, long long X) {
  mem[X]--;
  if (mem[X] == 0) mem.erase(X);
}
int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  long long N;
  cin >> N;
  vi A(N);
  vector<char> op(N);
  for (long long i = (long long)(0); i < (long long)(N - 1); i++)
    cin >> A[i] >> op[i];
  cin >> A[N - 1];
  vii dp(N, vi(3, -inf));
  dp[0][0] = A[0];
  for (long long i = (long long)(1); i < (long long)(N); i++) {
    if (op[i - 1] == '+') {
      dp[i][0] = std::max({dp[i - 1][0], dp[i - 1][1], dp[i - 1][2]}) + A[i];
      dp[i][1] = dp[i - 1][1] - A[i];
      dp[i][2] = dp[i - 1][2] + A[i];
    } else {
      dp[i][0] = dp[i - 1][0] - A[i];
      dp[i][1] = std::max(dp[i - 1][0] - A[i], dp[i - 1][1] + A[i]);
      dp[i][2] = std::max(dp[i - 1][2] + A[i], dp[i - 1][1] + A[i]);
    }
  }
  long long ans = -inf;
  for (long long i = (long long)(0); i < (long long)(3); i++)
    ans = std::max(ans, dp[N - 1][i]);
  cout << ans << "\n";
}
