#include <fstream>
#include <string.h>
#include <algorithm>
using namespace std;
ifstream f("next.in");
ofstream g("next.out");
long long D;
int N[1000002],V[18];
char Aux[1000002];
void Swap(int& x,int& y)
{
    int aux;
    aux=x;
    x=y;
    y=aux;
}
bool is_digit(char ch)
{
    return ch>='0' && ch<='9';
}
void Read()
{
    int i=0;
    f>>noskipws;
    char ch;
    while(1)
    {
        f>>ch;
        if(is_digit(ch)==1)
            break;
    }
    while(ch!='\n')
    {
        N[++N[0]]=ch-'0';
        f>>ch;
    }
    for(i=1;i<=N[0];i++)
        if(i<=N[0]/2)
            Swap(N[i],N[N[0]-i+1]);
    f>>D;
}
void add(int A[], int B[])
{
      int i, t = 0;
      for (i=1; i<=A[0] || i<=B[0] || t; i++, t/=10)
              A[i] = (t += A[i] + B[i]) % 10;
      A[0] = i - 1;
}
void AtribValue(int H[], long long X) {
  H[0] = 0;
  while (X) {
      ++H[0];
      H[H[0]] = X % 10;
      X /= 10;
  }
}
long long Mod(int A[],long long X)
/* Intoarce A%X */
{ int i;
  unsigned long R=0;

  for (i=A[0];i;i--)
    R=(10*R+A[i])%X;
  return R;
}
void Solve()
{
    long long Rest=Mod(N,D);
    if(Rest!=0)
        AtribValue(V,D-Rest);
    else
        V[0]=1;
    add(N,V);
    for(int i=N[0];i>=1;i--)
        g<<N[i];
    g<<"\n";
}
int main()
{
    Read();
    Solve();
   /*for(int i=1;i<=99999;i++)
        g<<9;
    g<<"\n";
    g<<10000000000000000;*/
    return 0;
}