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

// dfmt off
T lread(T = long)(){return readln.chomp.to!T();}
T[] lreads(T = long)(long n){return generate(()=>readln.chomp.to!T()).take(n).array();}
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;}}
alias sread = () => readln.chomp();enum MOD = 10 ^^ 9 + 7;
alias PQueue(T, alias less = "a<b") = BinaryHeap!(Array!T, less);
// dfmt on

void main()
{
    long N = lread();
    auto A = aryread();
    long ans = long.max;
    {
        auto B = A.dup;
        long sum = B[0];
        long cost;
        foreach (i; 1 .. N)
        {
            if (0 < sum)
            {
                if (sum + B[i] < 0)
                {
                    sum += B[i];
                    continue;
                }
                long x = -1 - B[i] - sum;
                cost += abs(x);
                B[i] += x;
                sum += B[i];
            }
            else
            {
                if (0 < sum + B[i])
                {
                    sum += B[i];
                    continue;
                }
                long x = 1 - B[i] - sum;
                cost += abs(x);
                B[i] += x;
                sum += B[i];
            }
        }
        // writeln(cost);
        // writeln(B);
        ans = ans.min(cost);
    }
    {
        auto B = A.dup;
        long cost;
        if (0 < B[0])
        {
            cost += 1 + B[0];
            B[0] -= 1 + B[0];
        }
        else
        {
            cost += abs(1 - B[0]);
            B[0] += 1 - B[0];
        }
        long sum = B[0];
        foreach (i; 1 .. N)
        {
            if (0 < sum)
            {
                if (sum + B[i] < 0)
                {
                    sum += B[i];
                    continue;
                }
                long x = -1 - B[i] - sum;
                cost += abs(x);
                B[i] += x;
                sum += B[i];
            }
            else
            {
                if (0 < sum + B[i])
                {
                    sum += B[i];
                    continue;
                }
                long x = 1 - B[i] - sum;
                cost += abs(x);
                B[i] += x;
                sum += B[i];
            }
        }
        // writeln(cost);
        // writeln(B);
        ans = ans.min(cost);
    }
    writeln(ans);
}
