1697⑨ to write.

 time limit: 1 sspace limit: 128000 KBtitle level: Golden Gold SolvingView Run Results  Title Description Description

Qi Cirno (Ice Goblin) has the ability to control the air-conditioning. It is more dangerous to freeze a small thing in an instant than a normal goblin. had been releasing the air-conditioner around her always very cold.

Due to the following three points reason ...

• Qi Cirno's Fuca symbol "Icicle Fall"-easy of the bomb screen is enough stupid, as long as standing in front of her there is no play will touch you;

• Zun in "Red Devil Township" introduced her when she said she was a bit stupid;

• In the Zun release "Oriental Phantasmagoria Tomb" Introduction map, in the picture put the Qi Lulu in the position of ⑨, and with "⑨ idiot" simple take, from "⑨" and "idiot" became her alias ...

So Kiki Cirno got the nickname of "idiot".

One day, Kiki Cirno again 2 ...

She wrote n letters to be loaded into N envelopes, but all were wrong ... Now you want to know how many kinds of possibilities are wrong.

Enter a description input Description

Number of letters and envelopes N.

outputs description output Description

The number of possibilities to mount the error.

sample input to sample

Input Example 1 2

Input Example 2 4

Sample output Sample outputs

Output Example 1 1

Output Example 2 9

data size & Hint

1≤n≤100

Code: (This problem applies the high-precision added to the equation solution, the code does not increase the precision operation)

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace Std;
int n,f[110];
int dp (int i)
{
if (i==1) return f[1];
if (i==2) return f[2];
else return f[i]= (i-1) * (DP (I-1) +DP (i-2));
}
int main ()
{
scanf ("%d", &n);
F[1]=0;f[2]=1;
printf ("%d", DP (n));
return 0;
}

1697⑨ to write.