#include <stdio.h>
int main(){
    //input
    long N,M;
    scanf("%ld %ld",&N,&M);

    //number of 1000 yen
    long t1 = (N-N%1000)/1000;

    //number of 1000 yen per 1 person
    long t2 = (t1-t1%M)/M;

    //total money per 1 person
    long total = 1000*t2;

    //ouput
    printf("%ld\n",total);
    return 0;
}