1 #include<cstdio>
 2 #include<iostream>
 3 #include<algorithm>
 4 #include<cmath>
 5 #include<cstring>
 6 #include<string>
 7 #include<stack>
 8 #include<vector>
 9 using namespace std;
10 
11 
12 int main()
13 {
14     int a,n;
15     scanf("%d%d",&a,&n);
16     int i,j=0,last=0;
17     int b[100005];
18     for(i=n;i>=1;i--)
19     {
20         b[j++]=(i*a+last)%10;
21         last=(i*a+last)/10;
22     }
23     if(last>0)
24         printf("%d",last);
25     for(i=j-1;i>=0;i--)
26         printf("%d",b[i]);
27     if(n==0)
28         printf("0");//别忘啦
29     printf("\n");
30     return 0;
31 }