#include <iostream> 
#include <fstream>   
int main() 
{     
 int board[10][10] = {0};       
 std::ifstream input("input.txt");       
 int n;     
 int x, y;       
 input >> n;       
 for (int i = 0; i < n; ++i)     
 {         
  input >> x >> y;           board[x][y] = 1;     
 }       
 input.close();       
 int p = 0;       
 for (int i = 1; i < 9; ++i)     
  {
   for (int j = 1; j < 9; ++j)         
   {             
     if (board[i][j] == 1)             
    {                 
      if (board[i - 1][j] == 0)                     ++p;
      if (board[i][j + 1] == 0)                     ++p;
      if (board[i + 1][j] == 0)                     ++p;
      if (board[i][j - 1] == 0)                     ++p;             
    }         
   }     
  }       
 std::ofstream output("output.txt");       
 output << p;       
 output.close();       
 return 0;

#include <iostream>
#include <fstream>
 
int main()
{
    int board[10][10] = {0};
 
    std::ifstream input("input.txt");
 
    int n;
    int x, y;
 
    input >> n;
 
    for (int i = 0; i < n; ++i)
    {
        input >> x >> y;
 
        board[x][y] = 1;
    }
 
    input.close();
 
    int p = 0;
 
    for (int i = 1; i < 9; ++i)
    {
        for (int j = 1; j < 9; ++j)
        {
            if (board[i][j] == 1)
            {
                if (board[i - 1][j] == 0)
                    ++p;
 
                if (board[i][j + 1] == 0)
                    ++p;
 
                if (board[i + 1][j] == 0)
                    ++p;
 
                if (board[i][j - 1] == 0)
                    ++p;
            }
        }
    }
 
    std::ofstream output("output.txt");
 
    output << p;
 
    output.close();
 
    return 0;

#include <iostream>
 
typedef long long  T_int;
 
T_int  get_prev_sum(T_int  sum, T_int F, T_int P)
{
    return  ((sum - F) / P + 1) * (F - P) + sum;        
}
 
int main()
{
    std::locale::global(std::locale(""));
    const T_int F_MAX = 1000000000;
    const T_int F_MIN = 2;
    const T_int P_MIN = 1;
 
    T_int F = 0;
    do
    {
        std::cout << "Стоимость полной бутылки F ("
                  << F_MIN 
                  << " <= F <= "
                  << F_MAX
                  << "): ";
        
        std::cin >> F;
    
    }while(   F < F_MIN
           || F_MAX < F);
 
    std::cout << std::endl;
 
    T_int P = 0;
    do
    {
        std::cout << "Стоимость пустой бутылки P ("
                  << P_MIN 
                  << " <= P < "
                  << F
                  << ")          : ";
        
        std::cin >> P;
    
    }while(   P < P_MIN
           || F <= P);
 
    T_int min_start_sum = F;
    for(T_int  i = 0; i < 4; ++i)
    {
        min_start_sum = get_prev_sum(min_start_sum, F, P);
    }
 
    std::cout << "Минимальная начальная сумма                      : "
              << min_start_sum
              << std::endl;

Const
 n=7;
 k=3;
Var
 s,s1,i:byte;
 m:word;
Begin
 m:=1;
 s1:=0;
 For i:=1 to 4 do
  begin
   s:=7;
   repeat
    Dec(s);
   until Frac((m*n+s1-s)/k)=0;
   m:=Round((m*n+s1-s)/k);
   s1:=s;
  end;
 Writeln(m*n+s);
 Readln
End.