ccf-201712-2
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
int main() {
int n,num;
cin>>n>>num;
int child[n+1];
memset(child,0,sizeof(child));
int sum=0;
while(1) {
int j=0,end;
for(int i=1; i<n+1; i++) {
if(child[i]==0) {
sum++;
if(sum%num==0||sum%10==num) {
child[i]=1;
if(j==0&&i==n){
j++;
end=i;
}
} else {
j++;
end=i;
}
}
}
if(j==1) {
cout<<end;
break;
}
}
return 0;
}