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;
  int b[N];
  
  for(int i=0;i<3;i++){
    scanf("%d",&A[0][i]);
  }
  
  for(int i=0;i<3;i++){
    scanf("%d",&A[1][i]);
  }
  
  for(int i=0;i<3;i++){
    scanf("%d",&A[2][i]);
  }
  
  scanf("%d",&N);
  
  for(int i=0; i<N; i++){
    scanf("%d",&b[i]);
  }

  for(int i=0;i<N;i++){
    for(int j=0;j<3;j++){
      for(int k=0;k<3;k++){
        if(b[i]==A[j][k]){
          A[j][k]=0;
        }
      }
    }
  }
  if((A[0][0]==0 && A[0][1]==0 && A[0][2]==0)||(A[1][0]==0 && A[1][1]==0 && A[1][2]==0)||(A[2][0]==0 && A[2][1]==0 && A[2][2]==0)){
    printf("Yes\n");
  }
  else if((A[0][0]==0 && A[1][0]==0 && A[2][0]==0)||(A[0][1]==0 && A[1][1]==0 && A[2][1]==0)||(A[2][0]==0 && A[2][1]==0 && A[2][2]==0)){
    printf("Yes\n");
  }
  else if((A[0][0]==0 && A[1][1]==0 && A[2][2]==0)||(A[0][2]==0 && A[1][1]==0 && A[2][0]==0)){
    printf("Yes\n");
  }
  else{
    printf("No\n");
  }
   
    return 0;
  }