#include <cstdio>
#include <cstring>
#include <algorithm>
#define Nmax 1000004
#define ull unsigned long long
using namespace std;
int n, i, j, v[Nmax], w[25];
ull k;
char s[Nmax];

void add(int A[], int B[])
{
      int i, t = 0;
      for (i=1; i<=A[0] || i<=B[0] || t; i++, t/=10)
              {
                  if (i > 9) B[i] = 0;
                  A[i] = (t += A[i] + B[i]) % 10;
              }
      A[0] = i - 1;
}

ull mod(int A[], ull B)
{
      ull i, t = 0;
      for (i = A[0]; i > 0; i--)
              t = (t * 10 + A[i]) * 1LL % B;
      return t;
}
int main()
{
    freopen("next.in", "r", stdin);
    freopen("next.out", "w", stdout);
    gets(s + 1);
    v[0] = strlen(s + 1);
    for (i = 1; i <= v[0]; ++i)
    v[v[0] - i + 1] = s[i] - '0';
    scanf("%lld", &k);
    ull val =  mod(v, k);
    if (val != 0) val = k - val;
    while (val)
    {
        w[ ++ w[0]] = val % 10;
        val /= 10;
    }
    add(v, w);
    for (i = v[0]; i >= 1; --i)
    printf("%d", v[i]);
    return 0;
}