#include <fstream>
#include <algorithm>
#define Nmax 1000005

using namespace std;

char sir[Nmax];
int a[Nmax],aux[50];
long long D;

inline void Convert(int a)
{
    while(a>0)
    {
        aux[++aux[0]]=a%10;
        a/=10;
    }
}

inline void Read()
{
    int i,aux,j;
    ifstream fin("next.in");
    fin.getline(sir, 1000005);
    for(i=0;sir[i];++i)
        a[++a[0]]=sir[i]-'0';
    i=1; j=a[0];
    while(i<j)
    {
        aux=a[i]; a[i]=a[j]; a[j]=aux;
        ++i; --j;
    }
    fin>>D;
    fin.close();
}

inline long long Modulo(int a[], int n, int p)
{
	int i,x=0,q;
	for(i=n;i>=1;i--)
	{
		x=x*10+a[i];
		q=x/p;
		x=x-q*p;
	}
	return x;
}

inline void Aduna(int a[], int &n, int b[], int m)
{
	int k,i,rest,x;
	k=max(n,m);rest=0;
	for(i=1;i<=k;i++)
	{
		x=a[i]+b[i]+rest;
		if(x>=10)
		{
			a[i]=x-10;
			rest=1;
		}
		else
		{
			a[i]=x;
			rest=0;
		}
	}
	n=k;
	if(rest)
		a[++n]=rest;
}

inline void Solve()
{
    int i;
    long long rest;
    rest=D-Modulo(a,a[0],D);
    if(rest!=D)
    {
        Convert(rest);
        Aduna(a,a[0],aux,aux[0]);
    }
    ofstream fout("next.out");
    for(i=a[0];i>0;--i)
        fout<<a[i];
    fout<<"\n";
    fout.close();
}

int main()
{
    Read();
    Solve();
    return 0;
}