import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;
import std.container;

alias sread = () => readln.chomp();
ulong bignum = 1_000_000_007;
alias Pair = Tuple!(long, "begin", long, "end");

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

void main()
{
    auto n = lread();
    auto a = aryread();
    long c_sum = a[0], change;
    foreach (e; a[1 .. $])
    {
        if (c_sum + e < 0)
        {
            if (c_sum > 0)
                c_sum += e;
            else
            {
                change += abs(1 - c_sum - e);
                c_sum = 1;
            }
        }
        else if(c_sum + e > 0)
        {
            if (c_sum < 0)
                c_sum += e;
            else
            {
                change += abs(-1 - c_sum - e);
                c_sum = -1;
            }
        }
        else
        {
            change += 1;
            if(c_sum < 0)
                c_sum = 1;
            else
                c_sum = -1;
        }
        // c_sum.writeln(" c_sum");
        // change.writeln(" change");
    }
    change.writeln();
}