using System;
using System.Linq;
using System.Collections.Generic;

namespace Contest
{
    class Program
    {
        static void Main(string[] args)
        {
            AGC015.A();
        }

        class AGC015
        {
            public static void A()
            {
                var N = Read.Long();
                var A = Read.Long();
                var B = Read.Long();
                Console.WriteLine((A > B || (N == 1 && A != B)) ? 0 : (N - 2) * (B - A) + 1);
            }
            public static void B()
            {
                var S = Read.Str();
                long N = S.Length;
                long count = N * (N - 1);
                for(int i = 0; i < N; ++i)
                {
                    count += S[i] == 'U' ? i : N - i - 1;
                }
                Console.WriteLine(count);
            }
            public static void C()
            {
                var N = Read.Int();
                var M = Read.Int();
                var Q = Read.Int();
                bool[,] S = new bool[N, M];
                for(int i = 0; i < N; ++i)
                {
                    var str = Read.Str();
                    for(int j = 0; j < M; ++j)
                    {
                        S[i, j] = str[j] == '1';
                    }
                }
                int[,] Ssum = new int[N + 1, M + 1];
                int[,] T1Sum = new int[N + 1, M];
                int[,] T2Sum = new int[N, M + 1];
                for(int i = 0; i < N; ++i)
                {
                    for(int j = 0; j < M; ++j)
                    {
                        Ssum[i + 1, j + 1] = Ssum[i + 1, j] + Ssum[i, j + 1] - Ssum[i, j] + (S[i, j] ? 1 : 0);
                    }
                }
                for (int i = 0; i < N; ++i)
                {
                    for (int j = 0; j < M -1; ++j)
                    {
                        T1Sum[i + 1, j + 1] = T1Sum[i + 1, j] + T1Sum[i, j + 1] - T1Sum[i, j] + (S[i, j] && S[i, j + 1] ? 1 : 0);
                    }
                }
                for (int i = 0; i < N -1; ++i)
                {
                    for (int j = 0; j < M; ++j)
                    {
                        T2Sum[i + 1, j + 1] = T2Sum[i + 1, j] + T2Sum[i, j + 1] - T2Sum[i, j] + (S[i, j] && S[i + 1, j] ? 1 : 0);
                    }
                }
                for(int q = 0; q < Q; ++q)
                {
                    var xy = Read.IntN();
                    var x1 = xy[0];
                    var y1 = xy[1];
                    var x2 = xy[2];
                    var y2 = xy[3];
                    var countS = Ssum[x2, y2] - Ssum[x1 - 1, y2] - Ssum[x2, y1 - 1] + Ssum[x1 - 1, y1 - 1];
                    var countT1 = T1Sum[x2, y2 - 1] - T1Sum[x1 - 1, y2 - 1] - T1Sum[x2, y1 - 1] + T1Sum[x1 - 1, y1 - 1];
                    var countT2 = T2Sum[x2 - 1, y2] - T2Sum[x1 - 1, y2] - T2Sum[x2 - 1, y1 - 1] + T2Sum[x1 - 1, y1 - 1];
                    Console.WriteLine(countS - countT1 - countT2);
                }
            }
            public static void D()
            {

            }
            public static void E()
            {

            }
            public static void F()
            {

            }
        }

        class Graph
        {
            public static int[] CalcDistance_OnTree(Dictionary<int, HashSet<int>> adj, int N, int start)
            {
                var dist = Enumerable.Range(0, N + 1).Select(i => -1).ToArray();
                dist[start] = 0;
                Queue<int> queue = new Queue<int>();
                queue.Enqueue(start);
                while (queue.Count > 0)
                {
                    var v = queue.Dequeue();
                    foreach (var w in adj[v])
                    {
                        if (dist[w] < 0)
                        {
                            dist[w] = dist[v] + 1;
                            queue.Enqueue(w);
                        }
                    }
                }
                return dist;
            }
        }

        static class Read
        {
            static Queue<string> queue = new Queue<string>();
            static void Enqueue() { var ss = Console.ReadLine().Split(' '); foreach (var s in ss) { queue.Enqueue(s); } }
            public static int Int() { if (queue.Count == 0) { Enqueue(); } return Convert.ToInt32(queue.Dequeue()); }
            public static long Long() { if (queue.Count == 0) { Enqueue(); } return Convert.ToInt64(queue.Dequeue()); }
            public static string Str() { if (queue.Count == 0) { Enqueue(); } return queue.Dequeue(); }
            public static int[] IntN() { return Console.ReadLine().Split(' ').Select(s => Convert.ToInt32(s)).ToArray(); }
            public static long[] LongN() { return Console.ReadLine().Split(' ').Select(s => Convert.ToInt64(s)).ToArray(); }
            public static string[] StrN() { return Console.ReadLine().Split(' '); }
            public static Tuple<int, int>[] TupleInt(int n) { List<Tuple<int, int>> list = new List<Tuple<int, int>>(); for (int i = 0; i < n; ++i) { var ab = Read.IntN(); list.Add(new Tuple<int, int>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<long, long>[] TupleLong(int n) { List<Tuple<long, long>> list = new List<Tuple<long, long>>(); for (int i = 0; i < n; ++i) { var ab = Read.LongN(); list.Add(new Tuple<long, long>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<string, string>[] TupleStr(int n) { List<Tuple<string, string>> list = new List<Tuple<string, string>>(); for (int i = 0; i < n; ++i) { var ab = Read.StrN(); list.Add(new Tuple<string, string>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<double, double>[] TupleDouble(int n) { List<Tuple<double, double>> list = new List<Tuple<double, double>>(); for (int i = 0; i < n; ++i) { var ab = Read.LongN(); list.Add(new Tuple<double, double>(ab[0], ab[1])); } return list.ToArray(); }
            public static long[,] LongMatrix(int r, int c)
            {
                var mat = new long[r, c];
                for (int i = 0; i < r; ++i)
                {
                    var x = Read.LongN();
                    for (int j = 0; j < c; ++j)
                    {
                        mat[i, j] = x[j];
                    }
                }
                return mat;
            }
            public static Dictionary<int, HashSet<int>> AdjacencyList(int N, int M)
            {
                Dictionary<int, HashSet<int>> dict = new Dictionary<int, HashSet<int>>();
                for (int i = 0; i <= N; ++i)
                {
                    dict.Add(i, new HashSet<int>());
                }
                for (int i = 0; i < M; ++i)
                {
                    var ab = Read.IntN();
                    dict[ab[0]].Add(ab[1]);
                    dict[ab[1]].Add(ab[0]);
                }
                return dict;
            }
            public static Dictionary<int, Dictionary<int, long>> AdjacencyListWithWeight(int N, int M)
            {
                Dictionary<int, Dictionary<int, long>> dict = new Dictionary<int, Dictionary<int, long>>();
                for (int i = 0; i <= N; ++i)
                {
                    dict.Add(i, new Dictionary<int, long>());
                }
                for (int i = 0; i < M; ++i)
                {
                    var ab = Read.IntN();
                    dict[ab[0]].Add(ab[1], ab[2]);
                    dict[ab[1]].Add(ab[0], ab[2]);
                }
                return dict;
            }
        }
    }
}


Measured memory_bytes: 11348