## Algorithm

In this problem you will be given two decimal integer number N, M. You will have to find the last non-zero digit of the P N M . This means no of permutations of N things taking M at a time. Input The input file contains several lines of input. Each line of the input file contains two integers N (0 ≤ N ≤ 20000000), M (0 ≤ M ≤ N). Input is terminated by end-of-file. Output For each line of the input file you should output a single digit, which is the last non-zero digit of P N M . For example, if P N M is 720 then the last non-zero digit is 2. So in this case your output should be 2.

Sample Input 10 10 10 5 25 6

Sample Output 8 4 2

## Code Examples

### #1 Code Example with C Programming

```Code - C Programming```

``````#include <bits/stdc++.h>

using namespace std;

int main()
{
int n,m;
while(scanf("%d %d",&n,&m) != EOF) {
long long res = 1;
for(int i=n;i>n-m;i--) {
res *= i;
while(res%10 == 0) res/=10;
res %= 1000000000;
}
printf("%d\n",res%10);
}
}``````
Copy The Code &

Input

cmd
10 10
10 5
25 6

Output

cmd
8
4
2