#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define fin "next.in"
#define fout "next.out"
#define NMAX 1000003

int N[NMAX];
long long D;
FILE *f,*g;

void write(int A[])
{
 g = fopen(fout,"w");
 for ( int i = A[0] ; i ; --i)
     fprintf(g,"%d",A[i]);
 fclose(g);
}

void reverse(int A[])
{
 int tmp;
 for ( int i = 1 ; i<=A[0] / 2 ; ++i )
    tmp = A[i] , A[i] = A[A[0] - i + 1] , A[A[0] - i + 1] = tmp;
}

void readData()
{
 f = fopen(fin,"r");
 char c;
 while((c=fgetc(f)) >= '0' & c <= '9')
   N[++N[0]] = c - '0';
 reverse(N);
 fscanf(f,"%Ld",&D);
}

void attrib(int A[] , long long x)         // A = x
{
 do
 {
  A[++A[0]] = x % 10;
  x /= 10;
 }
 while(x);
}

void add(int A[] , int B[]) // A = A + B
{
 int i,t;
 for ( i = 1 , t = 0 ;i<=A[0] | i<=B[0] | t ; ++i,t/=10)
    A[i] = (t += A[i] + B[i]) % 10;
 A[0] = i-1;
}

void mod(int X[], long long &Y, long long &R)      // R = X % Y
{
 for ( int i = X[0] ; i ; --i )
    {
     R = R * 10 + X[i];
     while(R>=Y) R-=Y;
    }
}

int C1[NMAX];

void solve()
{
 long long r = 0;
 mod(N,D,r);
 if(r)
 {
  attrib(C1,D - r);
  add(N,C1);
 }
 write(N);
}

int main()
{
 readData();
 solve();
 return 0;
}