#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>
#include <fstream>

using namespace std;
#define REP(i, n) for (int (i) = 0; (i) < (n); (i)++)
#define FOR(i, a, b) for (int (i) = (a); (i) < (b); (i)++)
#define RREP(i, a) for(int (i) = (a) - 1; (i) >= 0; (i)--)
#define FORR(i, a, b) for(int (i) = (a) - 1; (i) >= (b); (i)--)
#define DEBUG(C) cerr << #C << " = " << C << endl;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<LL>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using PII = pair<int, int>;
using PDD = pair<double, double>;
using PLL = pair<LL, LL>;
using VPII = vector<PII>;
template<typename T> using VT = vector<T>;
#define ALL(a) begin((a)), end((a))
#define RALL(a) rbegin((a)), rend((a))
#define SORT(a) sort(ALL((a)))
#define RSORT(a) sort(RALL((a)))
#define REVERSE(a) reverse(ALL((a)))
#define MP make_pair
#define FORE(a, b) for (auto &&a : (b))
#define FIND(s, e) ((s).find(e) != (s).end())
#define EB emplace_back
template<typename T> inline bool chmax(T &a, T b){if (a < b){a = b;return true;}return false;}
template<typename T> inline bool chmin(T &a, T b){if (a > b){a = b;return true;}return false;}

const int INF = 1e9;
const int MOD = INF + 7;
const LL LLINF = 1e18;

const int MAX = 1e5 + 10;
int n;
long long a[MAX];
pair<LL, LL> dp[MAX][2];
// (j == 0) +, (j == 1) -

int main(void) {
    scanf("%d", &n);
    REP(i, n) {
        scanf("%lld", a + i);
    }
    //REP(i, MAX)REP(j, 2) dp[i][j] = MP(LLINF, LLINF);
    if (a[0] == 0) {
        dp[0][0] = MP(1, 1);
        dp[0][1] = MP(-1, 1);
    } else if (a[0] > 0) {
        dp[0][0] = MP(a[0], 0);
        dp[0][1] = MP(-1, a[0] + 1);
    } else {
        dp[0][1] = MP(a[0], 0);
        dp[0][0] = MP(1, -a[0] + 1);
    }
    FOR(i, 1, n) {
        REP(j, 2) {
            if (a[i] + dp[i - 1][j].first == 0) {
                if (j == 0) {
                    dp[i][1] = MP(-1, dp[i - 1][j].second + 1);
                } else {
                    dp[i][0] = MP(1, dp[i - 1][j].second + 1);
                }
            } else if (a[i] + dp[i - 1][j].first > 0) {
                if (j == 0) {
                    dp[i][1] = MP(-1, dp[i - 1][j].second + a[i] + dp[i - 1][j].first + 1);
                } else {
                    dp[i][0] = MP(a[i] + dp[i - 1][j].first, dp[i - 1][j].second);
                }
            } else {
                if (j == 0) {
                    dp[i][1] = MP(a[i] + dp[i - 1][j].first, dp[i - 1][j].second);
                } else {
                    dp[i][0] = MP(1, dp[i - 1][j].second - (a[i] + dp[i - 1][j].first) + 1);
                }
            }
        }
    }
    cout << min(dp[n - 1][0].second, dp[n - 1][1].second) << endl;
}


Measured memory_bytes: 4096