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