#include <iostream>
#define N 10
using namespace std;
int path[N][N];
int main() {
    for (int i = 1; i < N; i++)
        path[i][0] = i;
    for (int j = 1; j < N; j++)
        path[0][j] = j;
    for (int i = 1; i < N; i++)
        for (int j = 1; j < N; j++)
            path[i][j] = path[i - 1][j] + path[i][j - 1];
    cout << path[8][4] << endl;
    return 0;
}