#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
typedef long long ll;
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#define ios ios_base::sync_with_stdio(0) ; cin.tie(0) ; cout.tie(0)
#define so sizeof
#define pb push_back
#define cl clear() ;
#define vl vector<ll>
#define sz size()
#define len length()
#define emp empty()
#define el endl;cout.flush()
#define be begin()
#define fi first
#define se second
#define br break
#define en end()
#define ro return 0
#define eb emplace_back
#define con continue
#define ms(x) memset(x , 0, so x)
#define all(x) (x).be , (x).en
#define acc(x) accumulate((x).be , (x).en , 0ll)
#define forn(i,a,b) for(ll i=a;i<=b;++i)
#define rng_58 mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())
#define vll vector<pair<ll,ll> >
#define pll pair<ll,ll>
#define plll pair<ll,pair<ll,ll>>
#define plvl pair<pair<ll,ll> ,ll>
#define mp make_pair
#define trace3(a,b,c) cerr <<"a is " << a << " b is " << b << " c is " << c << el;
#define trace4(a,b,c,d) cerr <<"a is " << a << " b is " << b << " c is " << c <<" d is " << d << el ;
#define trace5(a,b,c,d,e) cerr <<"a is " << a << " b is " << b << " c is " << c <<" d is " << d << " e is " << e << el;
#define trace6(a,b,c,d,e,f) cerr <<"a is " << a << " b is " << b << " c is " << c <<" d is " << d << " e is " << e << " f is " << f << el ;

ll even(vl v)
{
    ll n ;
    n = v.sz ;
    ll pref[n+1] ;
    ms(pref);

    ll ans = 0 ;
    pref[0] = v[0] ;
    if(v[0] == 0 ){
        v[0] = -1 ;
        ans = ans + 1 ;
    }
    else if(v[0] > 0){
        ans = ans + v[0] + 1 ;
        v[0] = -1 ;
    }
    pref[0] = v[0] ;
    forn(i , 1 , n -1 ){
       ll sum = pref[i-1] + v[i] ;
       if(i % 2 == 1){
          if(sum <= 0){
            ll changes = abs(sum) + 1 ;
            ans = ans + changes ;
            v[i] = v[i] + changes ;
          }
          pref[i] = pref[i-1] + v[i] ;
       }
       else if(i % 2 == 0){
          if(sum >= 0){
            ll changes = sum + 1;
            ans = ans + changes ;
            v[i] = v[i ] - changes ;
          }
          pref[i] = pref[i-1] +  v[i] ;
       }
    }
    return ans ;
}
ll odd(vl v)
{
    ll n ;
    n = v.sz ;
    ll pref[n+1] ;
    ms(pref);
    ll ans = 0 ;
    pref[0] = v[0] ;
    if(v[0] == 0){
        v[0] = 1;
        ans = ans + 1 ;
    }
    else if(v[0] < 0){
        ans =  ans + abs(v[0]) + 1 ;
        v[0] = 1;
    }
    pref[0] = v[0] ;
    forn(i , 1 , n-1){
       ll sum = pref[i-1] + v[i] ;
       if(i % 2 == 1){
          if(sum >= 0){
             ll changes = sum + 1;
             ans = ans + changes ;
             v[i] = v[i] - changes ;
          }
          pref[i]  = pref[i-1] + v[i] ;
       }
       else if(i % 2 == 0){
          if(sum <= 0){
            ll changes = abs(sum ) + 1 ;
            ans = ans + changes ;
            v[i] = v[i] + changes;
          }
          pref[i] = pref[i-1] + v[i] ;
       }
    }
    return ans ;
}

int main()
{
    ios;
    ll n ;
    cin >>n ;
    vl v;
    forn(i , 1 , n ) {
       ll x;
       cin >> x;
       v.pb(x) ;
    }
    ll foo = odd(v) ;
    ll ziz = even(v) ;
    ll ans = min(foo , ziz ) ;
    cout << ans << el ;

}


Measured memory_bytes: 2676