Problem:
Score : 100 points

Problem Statement

Takahashi wants to print a document with N pages double-sided, where two pages of data can be printed on one sheet of paper.

At least how many sheets of paper does he need?

Constraints

N is an integer.

1 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer.

Sample Input 1

5

Sample Output 1

3

By printing the 1-st, 2-nd pages on the 1-st sheet, 3-rd and 4-th pages on the 2-nd sheet, and 5-th page on the 3-rd sheet, we can print all the data on 3 sheets of paper.

Sample Input 2

2

Sample Output 2

1

Sample Input 3

100

Sample Output 3

50

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.io.InputStream;
import java.io.IOException;
import java.util.NoSuchElementException;

public class Main {
    public static void main(final String[] args) {
        final MyScanner sc = new MyScanner();
        final int n = sc.nextInt();
        System.out.println(n / 2 + n % 2);
    }
}

class MyScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int pointer = 0;
    private int bufLength = 0;

    private boolean hasNextByte() {
        if (pointer < bufLength) {
            return true;
        } else {
            pointer = 0;
            try {
                bufLength = in.read(buffer);
            } catch (final IOException e) {
                e.printStackTrace();
            }
            if (bufLength <= 0) {
                return false;
            }
        }
        return true;
    }

    private int readByte() {
        if (hasNextByte()) {
            return buffer[pointer++];
        } else {
            return -1;
        }
    }

    private static boolean isNumberChar(final int c) {
        return '0' <= c && c <= '9';
    }

    private static boolean isPrintableChar(final int c) {
        return 33 <= c && c <= 126;
    }

    public boolean hasNext() {
        while (hasNextByte() && !isPrintableChar(buffer[pointer])) {
            pointer++;
        }
        return hasNextByte();
    }

    public String next() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        final StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    public long nextLong() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        long num = 0;
        boolean isNegative = false;
        int b = readByte();
        if (b == '-') {
            isNegative = true;
            b = readByte();
        }
        if (!isNumberChar(b)) {
            throw new NumberFormatException();
        }
        while (true) {
            if (isNumberChar(b)) {
                num *= 10;
                num += b - '0';
            } else if (b == -1 || !isPrintableChar(b)) {
                return isNegative ? -num : num;
            } else {
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }

    public int nextInt() {
        final long temp = nextLong();
        if (temp < Integer.MIN_VALUE || Integer.MAX_VALUE < temp) {
            throw new NumberFormatException();
        }
        return (int) temp;
    }

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