#include<bits/stdc++.h>
using namespace std;

long long int solve(long long int n,long long int m)
{
    long long int x=1;
    m=m*1000*x;
    while(n/m>1)
    {
        m=m*x;
        x++;
    }
    return (x-1)*1000;
}
int main()
{
    long long int n,m;
    cin>>n>>m;
    cout<<solve(n,m);
}