#include "bits/stdc++.h"

#ifdef WINT_MIN
#define __MAI
#endif

using namespace std;
typedef unsigned int uint;
typedef long long int ll;
typedef unsigned long long int ull;

#define debugv(v) printf("L%d %s => ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;
#define debugm(m) printf("L%d %s is..\n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) printf("L%d %s is => ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;
#define debugaa(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}
#define debugaar(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[y][x]<<" ";}cout<<endl;}
#define ALL(v) (v).begin(),(v).end()
#define repeat(l) for(auto cnt=0;cnt<(l);++cnt)
#define BIGINT 0x7FFFFFFF
#define E107 1000000007ll
void printbit(int u) { if (u == 0)cout << 0; else { int s = 0, k = 0; for (; 0<u; u >>= 1, k++)s = (s << 1) | (u & 1); for (; 0<k--; s >>= 1)cout << (s & 1); } }template<typename T1, typename T2>
    ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << "(" << p.first << ":" << p.second << ")"; return o; }

#define TIME chrono::system_clock::now()
#define MILLISEC(t) (chrono::duration_cast<chrono::milliseconds>(t).count())

namespace {
    std::chrono::system_clock::time_point t;
    void tic() { t = TIME; }
    void toc() { fprintf(stderr, "TIME : %lldms\n", MILLISEC(TIME - t)); }
    std::chrono::system_clock::time_point tle = TIME;
#ifdef __MAI
    void safe_tle(int msec) { assert(MILLISEC(TIME - tle) < msec); }
#else
#define safe_tle(k) ;
#endif
}

#ifndef __MAI 
namespace {
    class MaiScanner {
    public:
        template<typename T>
        void input_integer(T& var) {
            var = 0;
            T sign = 1;
            int cc = getchar_unlocked();
            for (; cc<'0' || '9'<cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc&&cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var*sign;
        }
        void ign() { getchar_unlocked(); }
        MaiScanner& operator>>(int& var) {
            input_integer<int>(var);
            return *this;
        }
        MaiScanner& operator>>(long long& var) {
            input_integer<long long>(var);
            return *this;
        }
    };
}
MaiScanner scanner;
#else
#define scanner cin
#endif

int width, height;
int m, n;

ll aa[100010];

int main() {
    int i, j, k;
    int x, y, a, b;

    scanner >> n;

    repeat(n) {
        scanner >> aa[cnt];
    }

    ll r = 0;
    ll s = aa[0];
    if (aa[0] != 0) {

        ll r1, r2;

        r = 0;
        s = aa[0];
        if (s > 0) {
            r = s + 1;
            s = -1;
        }
        for (i = 1; i < n; ++i) {
            if (s < 0 && s + aa[i] < 0) {
                r += -s - aa[i] + 1;
                s = 1;
            }
            else if (s > 0 && s + aa[i] > 0) {
                r += s + aa[i] + 1;
                s = -1;
            }
            else {
                if (s + aa[i] != 0)
                    s += aa[i];
                else if (s > 0) {
                    s = -1;
                    ++r;
                }
                else {
                    s = 1;
                    ++r;
                }
            }
        }
        if (s == 0) ++r;
        r1 = r;


        r = 0;
        s = aa[0];
        if (s < 0) {
            r = -s + 1;
            s = 1;
        }
        for (i = 1; i < n; ++i) {
            if (s < 0 && s + aa[i] < 0) {
                r += -s - aa[i] + 1;
                s = 1;
            }
            else if (s > 0 && s + aa[i] > 0) {
                r += s + aa[i] + 1;
                s = -1;
            }
            else {
                if (s + aa[i] != 0)
                    s += aa[i];
                else if (s > 0) {
                    s = -1;
                    ++r;
                }
                else {
                    s = 1;
                    ++r;
                }
            }
        }
        if (s == 0) ++r;
        r2 = r;
        cout << min(r1,r2) << endl;
    }
    else {
        ll r1, r2;

        r = 1;
        s = 1;
        for (i = 1; i < n; ++i) {
            if (s < 0 && s + aa[i] < 0) {
                r += -s - aa[i] + 1;
                s = 1;
            }
            else if (s > 0 && s + aa[i] > 0) {
                r += s + aa[i] + 1;
                s = -1;
            }
            else {
                if (s + aa[i] != 0)
                    s += aa[i];
                else if (s > 0) {
                    s = -1;
                    ++r;
                }
                else {
                    s = 1;
                    ++r;
                }
            }
        }
        if (s == 0) ++r;
        r1 = r;

        r = 1;
        s = -1;
        for (i = 1; i < n; ++i) {
            if (s < 0 && s + aa[i] < 0) {
                r += -s - aa[i] + 1;
                s = 1;
            }
            else if (s > 0 && s + aa[i] > 0) {
                r += s + aa[i] + 1;
                s = -1;
            }
            else {
                if (s + aa[i] != 0)
                    s += aa[i];
                else if (s > 0) {
                    s = -1;
                    ++r;
                }
                else {
                    s = 1;
                    ++r;
                }
            }
        }
        if (s == 0) ++r;
        r2 = r;

        cout << min(r1, r2) << endl;
    }

    return 0;
}

Measured memory_bytes: 1024