#include<stdio.h>

int main(void){

//予算がN ,親戚の子供M 

long long int N,M;
long long int otoshidama;

scanf("%lld%lld",&N,&M);

otoshidama=N/M;

if(otoshidama>=1000){
otoshidama/=1000;
otoshidama*=1000;
printf("%lld",otoshidama);
}
else
printf("0");

return 0;

}