#include<cstdio>
#include<cstring>
#define maxn 1000035

using namespace std;

int a[maxn],b[maxn];

long long i,j,d,n;

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

void add(int A[], int B[])
{
      long long 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;
}

int main()
{
    freopen("next.in","r",stdin);
    freopen("next.out","w",stdout);
    char *x;
    x=new char[1000005];
    for(i=1;x[i-1]!='\n';i++)  scanf("%c",&x[i]);
    --i;--i;
    n=i;
    for(i=n;i>=1;--i)
        a[++a[0]]=x[i]-'0';

    delete x;

    fscanf(stdin,"%lld",&d);

    if(i=mod(a,d))
    {
        d=d-i;
        while(d)
            b[++b[0]]=d%10,d/=10;
        add(a,b);
    }

    for(i=a[0];i;--i)
        printf("%d",a[i]);

    printf("\n");

    fclose(stdin);
    fclose(stdout);

    return 0;
}