#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>

typedef long long int ll;

ll MAX(ll a, ll b){return a>b?a:b;}
ll MIN(ll a, ll b){return a>b?b:a;}
int compare(const void* a, const void* b){return *(int*)a - *(int*)b;}
ll digits(ll a){ll tmp=a; ll cnt=0; while(tmp>0){tmp/=10; cnt+=1;} return cnt;}

int main(void){
    ll n,m;
    scanf("%lld%lld", &n,&m);

    ll cnt = 0;
    while(cnt*1000*m <= n){
        cnt += 1;
    }

    printf("%lld\n", (cnt-1)*1000);
}