#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
ifstream f ("next.in");
ofstream g ("next.out");
typedef unsigned char cifra;
const int MAXN = 1000000;
cifra N[MAXN + 2];
char c[MAXN + 2];
long long D, rest;
int lN;

void afisare (cifra A[], int lA)
{
    for (int i = lA; i >= 1; i--)
        g << int(A[i]);
}

void citire()
{
    f >> c;
    lN = strlen (c);
    for (int i = lN - 1; i >= 0; i--)
        N[lN - i] = c[i] - '0';

    f >> D;

}

long long mod (cifra A[], long long B, int lA)
{
    long long t = 0;
    int i;
    for (i = lA; i >= 1; i--)
        t = (t * 10 + A[i]) % B;
    return t;
}

void add (cifra A[], long long t, int lA)
{
    int i;
    for (i = 1; i <= lA || t; i++, t /= 10)
        A[i] = (t += A[i]) % 10;
    lA = i - 1;
    afisare (A, lA);

}

int main()
{
    citire();
    rest = mod (N, D, lN);
    rest = D - rest;
    if (rest == D) rest = 0;

    add (N, rest, lN);

    return 0;
}