#include <cstdio>
#include <cstring>
const int nmax=1000000;
 
using namespace std;
 
class Hugen
{
    private:
		int x0;
        char x[nmax+5];
    public:
        Hugen()
        {
            x0=0;
        }
        Hugen(long long nr)
        {
        	x0=0;
            do
            {
                x[++x0]=nr%10;
                nr/=10;
            }while(nr);
        }
        void print()
        {
            int i;
            for(i=x0;i>=1;i--)
                printf("%d", x[i]);
            printf("\n");
        }
        Hugen operator+=(Hugen &other);
        long long operator%(long long k);
        void read();
};
void Hugen::read()
{
	x0=0;
    char c;
    while (scanf("%c",&c)!=EOF && c!='\n'){
        c=c-'0';
        x[(int)++x0]=c;
    }
    for (int i=1;i<=(x0>>1);i++){
        char aux;
        aux=x[i];
        x[i]=x[x0-i+1];
        x[x0-i+1]=aux;
    }
}
Hugen Hugen::operator += (Hugen &other){
    x0=(x0 > other.x0 ? x0 : other.x0);
    int tr=0;
    for (int i=1;i<=x0;i++){
        tr=x[i]+other.x[i]+tr;
        x[i]=tr%10;
        tr=tr/10;
    }
    if (tr){
        x[(int)++x0]=tr;
    }
    return *this;
}
long long Hugen::operator%(long long k)
{
    int i;
    long long r=0;
    for(i=x0;i>=1;i--)
        r=(r*10+x[i])%k;
    return r;
}
char s[nmax+1];
 
int main()
{
    freopen("next.in", "r", stdin);
    freopen("next.out", "w", stdout);
    long long d, r;
    
	Hugen n;
    n.read();
    scanf("%lld",&d);
    r=n%d;
    if (r==0){
        r=d;
    }
    r=d-r;
    Hugen ot(r);
    n+=ot;
    n.print();
     
    return 0;
}