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

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

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

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

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