#include<cstdio>
#include<cstring>
char a[1000004];
int n;	
long long mod(long long d){
   long long md=0;
   int i;
   for(i=n;i>=1;i--){
      md=md*10+a[i];
      md%=d;
   }
   return md;
}
	
void adun(long long x){
   long long c=x,el;
   int i;
   for(i=1;i<=n;i++){
      el=a[i]+c;
      c=el/10;
      a[i]=el%10;
   }
   while(c!=0){
      n++;
      a[n]=c%10;
      c/=10;
   }
}
	
int main(){
   int i,j,aux;
   long long d,md;
   freopen("next.in","r",stdin);
   freopen("next.out","w",stdout);
   scanf("%s",a);
   n=strlen(a);
   for(i=n;i>=1;i--)
      a[i]=a[i-1]-'0';
   for(i=1,j=n;i<j;i++,j--){
      aux=a[i];
      a[i]=a[j];
      a[j]=aux;
   }
   scanf("%lld",&d);
   md=mod(d);	
   if(md!=0)	
      adun(d-md);	
   for(i=n;i>=1;i--)	
      printf("%d",a[i]);	
   return 0;	
}