#include<fstream.h>
//using namespace std;
ifstream f1 ("next.in");
ofstream f2 ("next.out");
int v[1000001],v2[1000001],vf[1000001];
long long mod(int v[1000001], long long b)
{
      long long i;
      long long t = 0;
      for (i = 1; i<=v[0]; i++)
	t = (t*10 + v[i]) % b;
      return t;}
void suma()
 {
       long long i, t = 0;
       for (i=1; i<=vf[0] || i<=v2[0] || t; i++, t/=10)
	  {
	   vf[i] = (t +=vf[i]+v2[i])%10;
           }
       vf[0]=i-1;
}  
int main()
{

   long long i;
   long long d,t,x;
   char c;
   i=0;
   while (f1.get(c) && int(c)>=48) {i++; v[i]=int(c)-48;}
   v[0]=i;
   f1>>d;
   t=mod(v,d);
   t=(d-t)%d;
   for (i=1; i<=v[0]; i++) vf[i]=v[v[0]-i+1];
   x=v[0];
   i=0;
   while (t!=0) {i++; v2[i]=t%10; t/=10;}
   v2[0]=i;
   vf[0]=v[0];
   suma();
   for (i=vf[0]; i>=1; i--) f2<<vf[i];
   return 0;
}