using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
//using System.Drawing;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;

//using System.Threading;

namespace ReadWriteTemplate
{
    public static class Solver
    {
        private static void SolveCase()
        {
            long n = ReadLong();
            long a = ReadLong();
            long b = ReadLong();

            if (n == 1)
            {
                Writer.WriteLine(a == b ? 1 : 0);
                return;
            }

            long min = a * (n - 1) + b;
            long max = a + b * (n - 1);

            long ans = max - min + 1;
            Writer.WriteLine(ans > 0 ? ans : 0);
        }

        public class Point
        {
            public Point(int x, int y)
            {
                X = x;
                Y = y;
            }

            public int X;

            public int Y;

            protected bool Equals(Point other)
            {
                return X == other.X && Y == other.Y;
            }

            public override bool Equals(object obj)
            {
                if (ReferenceEquals(null, obj))
                {
                    return false;
                }
                if (ReferenceEquals(this, obj))
                {
                    return true;
                }
                if (obj.GetType() != this.GetType())
                {
                    return false;
                }
                return Equals((Point) obj);
            }

            public override int GetHashCode()
            {
                unchecked
                {
                    return (X * 397) ^ Y;
                }
            }
        }

        public static class Standard
        {
            public static long Power(long x, long p, long mod)
            {
                long result = 1;
                while (p > 0)
                {
                    if ((p & 1) == 0)
                    {
                        x = (x * x) % mod;
                        p >>= 1;
                    }
                    else
                    {
                        result = (result * x) % mod;
                        p--;
                    }
                }
                return result;
            }

            public static long Gcd(long a, long b)
            {
                return b == 0 ? a : Gcd(b, a % b);
            }

            public static List<int> GetPrimes(int n)
            {
                bool[] isPrime = Enumerable.Repeat(true, n).ToArray();
                isPrime[0] = false;
                isPrime[1] = false;
                for (int i = 2; i < n; i++)
                {
                    if (isPrime[i])
                    {
                        for (int j = i + i; j < n; j += i)
                        {
                            isPrime[j] = false;
                        }
                    }
                }
                List<int> primes = new List<int>();
                for (int i = 0; i < n; i++)
                {
                    if (isPrime[i])
                    {
                        primes.Add(i);
                    }
                }
                return primes;
            }
        }

        public static void Solve()
        {
            //int T = ReadInt();
            //for (int i = 0; i < T; i++)
            {
                //Writer.Write("Case #{0}: ", i + 1);
                SolveCase();
            }
        }

        public static void Main()
        {
            //Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;

#if DEBUG
            //Reader = Console.In; Writer = Console.Out;
            Reader = File.OpenText("input.txt"); Writer = File.CreateText("output.txt");
#else
            Reader = Console.In; Writer = Console.Out;
#endif

            Solve();

            Reader.Close();
            Writer.Close();
        }

        public static IOrderedEnumerable<TSource> OrderByWithShuffle<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
        {
            return source.Shuffle().OrderBy(keySelector);
        }

        public static T[] Shuffle<T>(this IEnumerable<T> source)
        {
            T[] result = source.ToArray();
            Random rnd = new Random();
            for (int i = result.Length - 1; i >= 1; i--)
            {
                int k = rnd.Next(i + 1);
                T tmp = result[k];
                result[k] = result[i];
                result[i] = tmp;
            }
            return result;
        }

        #region Read/Write

        private static TextReader Reader;

        private static TextWriter Writer;

        private static Queue<string> CurrentLineTokens = new Queue<string>();

        private static string[] ReadAndSplitLine()
        {
            return Reader.ReadLine().Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
        }

        public static string ReadToken()
        {
            while (CurrentLineTokens.Count == 0)
                CurrentLineTokens = new Queue<string>(ReadAndSplitLine());
            return CurrentLineTokens.Dequeue();
        }

        public static string ReadLine()
        {
            return Reader.ReadLine();
        }

        public static int ReadInt()
        {
            return int.Parse(ReadToken());
        }

        public static long ReadLong()
        {
            return long.Parse(ReadToken());
        }

        public static double ReadDouble()
        {
            return double.Parse(ReadToken(), CultureInfo.InvariantCulture);
        }

        public static int[] ReadIntArray()
        {
            return ReadAndSplitLine().Select(int.Parse).ToArray();
        }

        public static long[] ReadLongArray()
        {
            return ReadAndSplitLine().Select(long.Parse).ToArray();
        }

        public static double[] ReadDoubleArray()
        {
            return ReadAndSplitLine().Select(s => double.Parse(s, CultureInfo.InvariantCulture)).ToArray();
        }

        public static int[][] ReadIntMatrix(int numberOfRows)
        {
            int[][] matrix = new int[numberOfRows][];
            for (int i = 0; i < numberOfRows; i++)
                matrix[i] = ReadIntArray();
            return matrix;
        }

        public static string[] ReadLines(int quantity)
        {
            string[] lines = new string[quantity];
            for (int i = 0; i < quantity; i++)
                lines[i] = Reader.ReadLine().Trim();
            return lines;
        }

        public static void WriteArray<T>(IEnumerable<T> array)
        {
            Writer.WriteLine(string.Join(" ", array));
        }

        #endregion
    }
}


Measured memory_bytes: 13268