/*pku 2509  Peter's smokes  051210*/
#include<stdio.h>
int main()
{
    long n,nn,k;
    long sum,rst;
    for(;scanf("%ld%ld",&n,&k)!=EOF;)
    {
        for(sum=n,rst=0,nn=n;nn;sum+=(rst+nn)/k,rst=nn%k,nn/=k)
            ;
        printf("%ld\n",sum);
    }
}