#include <windows.h>
#pragma hdrstop
#include <fstream>
#include <iomanip>
#include "pt4.h"
void fil(double **a, int n)
{
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            a[i][j] = 0;
        }
    }
}

void way(ifstream &fin, double **a, int n)
{
    while(!fin.eof())
    {
        int i, j;
        fin >> i >> j;
        a[i - 1][j - 1] = -1;
    }

    bool fl = true;
    for (int i = 0; i < n && fl; i++)
    {
        if (a[0][i] == 0)
            a[0][i]++;
        else
            fl = false;

    }

    for (int i = 1; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            if (a[i][j] != -1.0)
            {
                if(j == 0)
                {
                    if (a[i - 1][j] == -1.0)
                    {
                        a[i][j] = -1.0;
                    }
                    else
                    {
                        a[i][j] += a[i - 1][j];
                    }
                }
                else
                {
                    if ((a[i - 1][j] == -1) && (a[i][j - 1] == -1))
                    {
                        a[i][j] = -1.0;
                    }
                    else if((a[i - 1][j] == -1) && (a[i][j - 1] != -1))
                    {
                        a[i][j] += a[i][j - 1];
                    }
                    else if((a[i - 1][j] != -1) && (a[i][j - 1] == -1))
                    {
                        a[i][j] += a[i - 1][j];
                    }
                    else
                    {
                        a[i][j] += (a[i][j - 1] + a[i - 1][j]);
                    }
                }
            }
        }
    }
}

void Solve()
{
    Task("Dyn7");
    string f1, f2;
    pt >> f1 >> f2;

    ifstream fin(f1.c_str());
    ofstream fout(f2.c_str());

    int n;
    fin >> n;
    double **a = new double *[n];
    for (int i = 0; i < n; i++)
        a[i] = new double[n];

    fil(a, n);

    way(fin, a, n);

    if(a[n - 1][n - 1] == -1)
        fout << 0;
    else
        fout << fixed << setprecision(0) << a[n - 1][n - 1];

}