Language: Java

    /**
     * Created by Karan Jobanputra on 29-05-2017.
     */

    import java.util.Scanner;
    import java.io.*;
    import java.util.*;
    import java.math.*;
    import java.lang.*;

    import static java.lang.Math.*;

    public class AtC015A {
        public static void main(String args[]) throws Exception {
            InputReader sc = new InputReader(System.in);
            PrintWriter pw = new PrintWriter(System.out);
            int n = sc.nextInt();
            int a = sc.nextInt();
            int b = sc.nextInt();
            if(n==1)
            {
                if(a==b) pw.println(1);
                else pw.println(0);
            }
            else
            {
                if(n>1)
                {
                    if(a>b)
                    {
                        pw.println(0);
                    }
                    else
                    {
                        int remaining = n-2;
                        int minSum = remaining*a;
                        int maxSum = remaining*b;
                        pw.println(maxSum-minSum+1);

                    }
                }
            }

            pw.close();
        }

        static class InputReader {
            private InputStream stream;
            private byte[] buf = new byte[1024];
            private int curChar;
            private int numChars;
            private SpaceCharFilter filter;

            public InputReader(InputStream stream) {
                this.stream = stream;
            }

            public int read() {
                if (numChars == -1)
                    throw new InputMismatchException();

                if (curChar >= numChars) {
                    curChar = 0;
                    try {
                        numChars = stream.read(buf);
                    } catch (IOException e) {
                        throw new InputMismatchException();
                    }

                    if (numChars <= 0)
                        return -1;
                }
                return buf[curChar++];
            }

            public String nextLine() {
                BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
                String str = "";
                try {
                    str = br.readLine();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                return str;
            }

            public int nextInt() {
                int c = read();

                while (isSpaceChar(c))
                    c = read();

                int sgn = 1;

                if (c == '-') {
                    sgn = -1;
                    c = read();
                }

                int res = 0;
                do {
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    res *= 10;
                    res += c - '0';
                    c = read();
                }
                while (!isSpaceChar(c));

                return res * sgn;
            }

            public long nextLong() {
                int c = read();
                while (isSpaceChar(c))
                    c = read();
                int sgn = 1;
                if (c == '-') {
                    sgn = -1;
                    c = read();
                }
                long res = 0;

                do {
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    res *= 10;
                    res += c - '0';
                    c = read();
                }
                while (!isSpaceChar(c));
                return res * sgn;
            }

            public double nextDouble() {
                int c = read();
                while (isSpaceChar(c))
                    c = read();
                int sgn = 1;
                if (c == '-') {
                    sgn = -1;
                    c = read();
                }
                double res = 0;
                while (!isSpaceChar(c) && c != '.') {
                    if (c == 'e' || c == 'E')
                        return res * Math.pow(10, nextInt());
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    res *= 10;
                    res += c - '0';
                    c = read();
                }
                if (c == '.') {
                    c = read();
                    double m = 1;
                    while (!isSpaceChar(c)) {
                        if (c == 'e' || c == 'E')
                            return res * Math.pow(10, nextInt());
                        if (c < '0' || c > '9')
                            throw new InputMismatchException();
                        m /= 10;
                        res += (c - '0') * m;
                        c = read();
                    }
                }
                return res * sgn;
            }

            public String readString() {
                int c = read();
                while (isSpaceChar(c))
                    c = read();
                StringBuilder res = new StringBuilder();
                do {
                    res.appendCodePoint(c);
                    c = read();
                }
                while (!isSpaceChar(c));

                return res.toString();
            }

            public boolean isSpaceChar(int c) {
                if (filter != null)
                    return filter.isSpaceChar(c);
                return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
            }

            public String next() {
                return readString();
            }

            public interface SpaceCharFilter {
                public boolean isSpaceChar(int ch);
            }
        }

        static class Node implements Comparable<Node> {
            int v;
            int w;

            Node(int v, int w) {
                this.v = v;
                this.w = w;
            }

            public int compareTo(Node node) {
                if (w == node.w)
                    return Integer.compare(v, node.v);

                return (-1) * Integer.compare(w, node.w);
            }
        }
    }

Compiler output:
Main.java:13: error: class AtC015A is public, should be declared in a file named AtC015A.java
    public class AtC015A {
           ^
1 error