import java.util.Scanner;
// 1:无需package
// 2: 类名必须Main, 不可修改
public class Main {
static int ans = 0;
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
//在此输入您的代码...
int[] res = new int[]{0,1,2,3,4,5,6,7,8,9};
f(0,res);
System.out.println(ans);
scan.close();
}
public static void f(int k,int[] res)
{
if(k>10)
{
return;
}
if(k==10)
{
if(check(res))
{
ans++;
return;
}
}
for(int i = k;i<res.length;i++)
{
int temp = res[i];
res[i] = res[k];
res[k] = temp;
f(k+1,res);
temp = res[k];
res[k] = res[i];
res[i] = temp;
}
}
public static boolean check(int[] res)
{
boolean match = false;
if(res[0]<res[1]&&res[0]<res[2]&&res[1]<res[3]&&res[1]<res[4]&&res[2]<res[4]&&res[2]<res[5]&&res[3]<res[6]&&res[3]<res[7]&&res[4]<res[7]&&res[4]<res[8]&&res[5]<res[8]&&res[5]<res[9])
{
match = true;
}
return match;
}
}