#include <stdio.h>
#include <string.h>
#define M 1000009 
#define m 40
char S[M];
short int H[m],K[m];
int N[M];
long long  D,R;
void sub(int A[M], short int H[m])
{
    int i, t = 0;
    for (i = 1; i <= A[0]; i++)
        A[i] += (t = (A[i] -= H[i] + t) < 0) * 10;
    for (; A[0] > 1 && !A[A[0]]; A[0]--);
}
void add(int A[M], short int B[m])
{
    int i, t = 0;
    for (i=1; i<=A[0] || i<=B[0] || t; i++, t/=10)
        A[i] = (t += A[i] + B[i]) % 10;
    A[0] = i - 1;
}
long long mod(int A[M], long long D)
{
    int i, t = 0;
    for (i = A[0]; i > 0; i--)
        t = (t * 10 + A[i]) % D;
    return t;
}
void transform(short int H[m], long long x)
{
	H[0]=0;
	do{
		H[++H[0]]=x%10;
		x/=10;
	}while(x);
}

int main()
{
	int i;
	freopen("next.in", "r", stdin);
	freopen("next.out", "w", stdout);
	scanf("%s\n", S);
	scanf("%lld", &D);
	N[0]=strlen(S);
	for(i=1;i<=N[0];++i)
		N[i]=(S[N[0]-i]-'0');
	R=mod(N,D);
	if(R>0)
	{
		transform(H,D);
	    add(N,H);
		transform(K,R);
		sub(N,K);
	}
	for(i=N[0];i>=1;--i)
		printf("%d", N[i]);
	return 0;
}