993 992 991
 100 1 10
 960 935 994
 99 8 99
 60 16 1
 759 10 258
 24 19 9
 196 169 144
 1000 999 1
 945 812 917
 1000 100 10
 500 300 300
 888 777 1000
 2 1 4
 24 12 12
 767 2 514
 2 1 2
 1000 1 1
 5 2 1
 70 32 1
 765 123 899
 17 7 10
 5 4 10
 888 777 888
 66 38 4
 1000 999 1000
 9 3 300
 244 87 4
 765 123 45
 1000 1 1000
 305 203 421
 100 10 1
 64 12 8
 894 1 999
 2 1 1
 18 14 10
 6 2 4
 888 777 1
 27 26 1
 2 1 3
 5 1 5
 7 3 200
 561 31 917
 17 10 7
 93 74 831

1
 990
 27
 1127
 3
 19325
 3
 24
 1
 151
 90
 200
 143
 4
 12
 196605
 2
 999
 2
 2
 4693
 15
 3
 127
 3
 2
 600
 8
 235
 999000
 212
 9
 35
 892107
 1
 3
 8
 1
 1
 3
 20
 267
 15678
 5
 214

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.StringTokenizer;
import java.util.TreeMap;

public class Main {
    Scanner in;
    PrintWriter out;

    void setIn(String fI) {

        try {
            in = new Scanner(new FileInputStream(new File(fI)));
        } catch (FileNotFoundException e) {
            throw new Error(e);
        }
    }

    void setIn() {
        in = new Scanner(System.in);
    }

    void setOut(String fO) {
        try {
            out = new PrintWriter(new FileWriter(fO));
        } catch (IOException e) {
            throw new Error(e);
        }
    }

    void setOut() {
        out = new PrintWriter(System.out);
    }

    class Scanner {
        StringTokenizer st;
        BufferedReader in;
        String del;

        Scanner(InputStream is) {
            in = new BufferedReader(new InputStreamReader(is));
            st = null;
            del = " \t\n\r\f";
        }

        void setDelimiters(String del) {
            this.del = del;
        }

        String next() {
            if (st == null || !st.hasMoreTokens()) {
                st = new StringTokenizer(nextLine(), del);
            }
            return st.nextToken();
        }

        String nextLine() {
            try {
                st = null;
                return in.readLine();
            } catch (IOException e) {
                throw new Error(e);
            }
        }

        char nextChar() {
            try {
                char ch = (char) in.read();
                while (del.indexOf(ch) >= 0)
                    ch = (char) in.read();
                return ch;
            } catch (IOException e) {
                throw new Error(e);
            }
        }

        boolean hasNext() {
            try {
                return in.ready() || (st != null && st.hasMoreTokens());
            } catch (IOException e) {
                throw new Error(e);
            }
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        BigInteger nextBigInteger() {
            return new BigInteger(next());
        }

        BigDecimal nextBigDecimal() {
            return new BigDecimal(next());
        }

        int[] nextIntArray(int len) {
            int[] a = new int[len];
            for (int i = 0; i < len; i++) {
                a[i] = nextInt();
            }
            return a;
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }
    }

    public static void main(String[] args) {
        new Main().run();
    }

    void run() {
        setIn();
        setOut();
        try {
            solve();
        } finally {
            out.close();
        }
    }

    void solve() {
        int a = in.nextInt();
        int b = in.nextInt();
        int c = in.nextInt();
        int k = 0;
        while ((k + b) * c < a * c) {
            k++;
        }
        out.println(k);
    }
}