import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.util.*;

public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        BigDecimal A;
        BigDecimal B;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            A = new BigDecimal(in.next());
            B = new BigDecimal(in.next());
            // A = new int[N];
            // for (int i = 0; i < N; i++) {
            // A[i] = in.nextInt();
            // }
            long ans = A.multiply(B).longValue();
            // ans.setScale(0,BigDecimal.ROUND_DOWN)
            out.println(ans);
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.OutputStream; OutputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.math.BigDecimal; BigDecimal java.math import java.util.*; util.* java public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        BigDecimal A;
        BigDecimal B;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            A = new BigDecimal(in.next());
            B = new BigDecimal(in.next());
            // A = new int[N];
            // for (int i = 0; i < N; i++) {
            // A[i] = in.nextInt();
            // }
            long ans = A.multiply(B).longValue();
            // ans.setScale(0,BigDecimal.ROUND_DOWN)
            out.println(ans);
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) Solver solver = new Solver(); solver new Solver() solver.solve(in, out) solver.solve solver in out out.close() out.close out String[] args args static class Solver {
        BigDecimal A;
        BigDecimal B;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            A = new BigDecimal(in.next());
            B = new BigDecimal(in.next());
            // A = new int[N];
            // for (int i = 0; i < N; i++) {
            // A[i] = in.nextInt();
            // }
            long ans = A.multiply(B).longValue();
            // ans.setScale(0,BigDecimal.ROUND_DOWN)
            out.println(ans);
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    } Solver BigDecimal A; A BigDecimal B; B // write your code
        void solve(InputReader in, PrintWriter out) {
            A = new BigDecimal(in.next());
            B = new BigDecimal(in.next());
            // A = new int[N];
            // for (int i = 0; i < N; i++) {
            // A[i] = in.nextInt();
            // }
            long ans = A.multiply(B).longValue();
            // ans.setScale(0,BigDecimal.ROUND_DOWN)
            out.println(ans);
        } solve {
            A = new BigDecimal(in.next());
            B = new BigDecimal(in.next());
            // A = new int[N];
            // for (int i = 0; i < N; i++) {
            // A[i] = in.nextInt();
            // }
            long ans = A.multiply(B).longValue();
            // ans.setScale(0,BigDecimal.ROUND_DOWN)
            out.println(ans);
        } A = new BigDecimal(in.next()) A new BigDecimal(in.next()) B = new BigDecimal(in.next()) B new BigDecimal(in.next()) long ans = A.multiply(B).longValue(); ans A.multiply(B).longValue() A.multiply(B).longValue A.multiply(B) A.multiply A B out.println(ans) out.println out ans InputReader in in PrintWriter out out void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        } debug {
            System.err.println(Arrays.deepToString(os));
        } System.err.println(Arrays.deepToString(os)) System.err.println System.err System System.err Arrays.deepToString(os) Arrays.deepToString Arrays os Object... os os static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }
    } InputReader BufferedReader reader; reader StringTokenizer tokenizer; tokenizer InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } InputReader {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } next {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } IOException e {
                    throw new RuntimeException(e);
                } throw new RuntimeException(e); new RuntimeException(e) {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        BigDecimal A;
        BigDecimal B;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            A = new BigDecimal(in.next());
            B = new BigDecimal(in.next());
            // A = new int[N];
            // for (int i = 0; i < N; i++) {
            // A[i] = in.nextInt();
            // }
            long ans = A.multiply(B).longValue();
            // ans.setScale(0,BigDecimal.ROUND_DOWN)
            out.println(ans);
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        BigDecimal A;
        BigDecimal B;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            A = new BigDecimal(in.next());
            B = new BigDecimal(in.next());
            // A = new int[N];
            // for (int i = 0; i < N; i++) {
            // A[i] = in.nextInt();
            // }
            long ans = A.multiply(B).longValue();
            // ans.setScale(0,BigDecimal.ROUND_DOWN)
            out.println(ans);
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

        long nextLong() {
            return Long.parseLong(next());
        }
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.util.*;

public class Main {
    // static int INF = (1 << 30) - 1;
    // static long L_INF = (1L << 62) - 1;
    // static long MOD = (long) 1e9 + 7;

    static class Solver {
        BigDecimal A;
        BigDecimal B;
        // int[] A;

        // write your code
        void solve(InputReader in, PrintWriter out) {
            A = new BigDecimal(in.next());
            B = new BigDecimal(in.next());
            // A = new int[N];
            // for (int i = 0; i < N; i++) {
            // A[i] = in.nextInt();
            // }
            long ans = A.multiply(B).longValue();
            // ans.setScale(0,BigDecimal.ROUND_DOWN)
            out.println(ans);
        }

        void debug(Object... os) {
            System.err.println(Arrays.deepToString(os));
        }
    }

    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(in, out);
        out.close();
    }

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

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