Fast Scanner

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.StringTokenizer;

class FastScanner {
    private BufferedReader br;
    private StringTokenizer tokenizer;

    FastScanner(InputStream stream) {
        br = new BufferedReader(new InputStreamReader(stream));
    }

    String readLine() {
        try {
            return br.readLine();
        } catch (IOException e) {
            return null;
        }
    }

    String nextToken() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(readLine());
        }
        return tokenizer.nextToken();
    }

    BigInteger nextBigInteger() {
        return new BigInteger(nextToken(), 10);
    }

    byte nextByte() {
        return Byte.parseByte(nextToken());
    }

    short nextShort() {
        return Short.parseShort(nextToken());
    }

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

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

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

    boolean hasMoreTokens() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            String s = readLine();
            if (s == null) {
                return false;
            }
            tokenizer = new StringTokenizer(readLine());
        }
        return tokenizer.hasMoreTokens();
    }
}