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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>

int main(void){
  int a[3][3],n,i,j,k;
  
  for(i=0;i<3;i++)
     for(j=0;j<3;j++)
       scanf("%d",&a[i][j]);
  
  scanf("%d",&n);
  int b[n];
  for(k=0;k<n;k++)
    scanf("%d",&b[k]);
  
  for(i=0;i<3;i++)
    for(j=0;j<3;j++)
      for(k=0;k<n;k++)
        if(a[i][j]==b[k])
          a[i][j]=0;
  
  for(i=0;i<3;i++){
    if(a[i][0]+a[i][1]+a[i][2]==0){
      printf("Yes\n");
      return 0;
    }
    else if(a[0][i]+a[1][i]+a[2][i]==0){
      printf("Yes\n");
      return 0;
    }
   }
  if(a[0][0]+a[1][1]+a[2][2]==0){
    printf("Yes\n");
    return 0;
  }
  else if(a[0][2]+a[1][1]+a[2][0]==0){
    printf("Yes\n");
    return 0;
  }
  printf("No\n");
  return 0;
}