using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Numerics;
using System.Text;
using System.Threading.Tasks;

namespace AtCorder
{
	public class Program
	{
		static void Main(string[] args)
		{
			var cin = new Scanner2();
			int n = cin.Int();
			long[] a = cin.ArrayLong(n);

			{
				bool ok = true;
				long sum = 0;
				for (int i = 0; i < n; i++) {
					long next = sum + a[i];
					if (next == 0 || sum * next >= 0) {
						ok = false;
						break;
					}

					sum = next;
				}

				if (ok) {
					Console.WriteLine(0);
					return;
				}
			}

			long ans1 = 0;
			{
				long current = a[0];
				if (current <= 0) {
					current = 1;
					ans1 += Math.Abs(a[0]) + 1;
				}
				for (int i = 1; i < n; i++) {
					long next = current + a[i];
					if (current * next < 0) {
						current = next;
						continue;
					}

					long temp = current * a[i];
					if (temp > 0) {
						ans1 += Math.Abs(a[i]) + Math.Abs(current) + 1;
						current = current > 0 ? -1 : 1;
					} else if (temp < 0) {
						ans1 += Math.Abs(current + a[i]) + 1;
						current = current > 0 ? -1 : 1;
					} else {
						ans1 += Math.Abs(current) + 1;
						current = current > 0 ? -1 : 1;
					}
				}
			}

			long ans2 = 0;
			{
				long current = a[0];
				if (current >= 0) {
					current = -1;
					ans2 += Math.Abs(a[0]) + 1;
				}
				for (int i = 1; i < n; i++) {
					long next = current + a[i];
					if (current * next < 0) {
						current = next;
						continue;
					}

					long temp = current * a[i];
					if (temp > 0) {
						ans2 += Math.Abs(a[i]) + Math.Abs(current) + 1;
						current = current > 0 ? -1 : 1;
					} else if (temp < 0) {
						ans2 += Math.Abs(current + a[i]) + 1;
						current = current > 0 ? -1 : 1;
					} else {
						ans2 += Math.Abs(current) + 1;
						current = current > 0 ? -1 : 1;
					}
				}
			}

			Console.WriteLine(Math.Min(ans1, ans2));
		}
	}

	public class Scanner2
	{
		private readonly char[] delimiter_ = new char[] { ' ' };
		private readonly string filePath_;
		private string[] buf_;
		private int index_;
		Func<string> reader_;

		public Scanner2(string file = "")
		{
			if (string.IsNullOrWhiteSpace(file)) {
				reader_ = Console.ReadLine;
			} else {
				filePath_ = file;
				var fs = new StreamReader(file);
				reader_ = fs.ReadLine;
			}
			buf_ = new string[0];
			index_ = 0;
		}

		public string Next()
		{
			if (index_ < buf_.Length) {
				return buf_[index_++];
			}

			string st = reader_();
			while (st == "") {
				st = reader_();
			}

			buf_ = st.Split(delimiter_, StringSplitOptions.RemoveEmptyEntries);
			if (buf_.Length == 0) {
				return Next();
			}

			index_ = 0;
			return buf_[index_++];
		}

		public int Int() => int.Parse(Next());
		public long Long() => long.Parse(Next());
		public double Double() => double.Parse(Next());

		public int[] ArrayInt(int N, int add = 0)
		{
			int[] Array = new int[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Int() + add;
			}
			return Array;
		}

		public long[] ArrayLong(int N, long add = 0)
		{
			long[] Array = new long[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Long() + add;
			}
			return Array;
		}

		public double[] ArrayDouble(int N, double add = 0)
		{
			double[] Array = new double[N];
			for (int i = 0; i < N; i++) {
				Array[i] = Double() + add;
			}
			return Array;
		}

		public void Save(string text)
		{
			if (string.IsNullOrWhiteSpace(filePath_)) {
				return;
			}

			File.WriteAllText(filePath_ + "_output.txt", text);
		}
	}
}

Measured memory_bytes: 29152