#include<stdio.h>
#include<iostream>
#include<string.h>

long long d, r, aux, lung;
int *a=new int[500010];
int *b=new int[170];
void citire()
{
  char s[500010];
  freopen("next.in","r",stdin);
  scanf("%s",&s);
  long long l;
  l=strlen(s);
  for (long long i=l-1; i>=0; i--)
    a[l-i]=s[i]-'0';
  lung=l;
  a[0]=l;
  scanf("%lld",&d);
}


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


void adunare()
 { int ct;
   int *s=new int [500040];
   long long i;
   ct = 0;
   memset (s, 0, sizeof(s));
   /*if (a[0]>b[0]) s[0] = a[0];
        else s[0]=b[0];
   for (i = 1; i <= s[0]; i++)
      { s[i] = a[i] + b[i] + ct;
	ct = s[i] / 10;
	s[i] = s[i] % 10;
      }

   if (ct) { s[0]++;
	     s[s[0]] = ct;
	   }*/
  freopen("next.out","w",stdout);
  for (i=s[0]; i>=1; i--)
     printf("%d",s[i]);
}


void transform()
{
  b[0]=0;
  while (aux)
    {
      b[0]++ ;
      b[b[0]]=aux%10;
      aux/=10;
    }
}


int main()
{
  citire();
  r=mod(a,d);
  aux=(d-r)%d;
  transform();
  adunare();
  return 0;
}