Peter's smoke

#include<stdio.h>
int main()
{
    long long int n,k,a,b,c,d,e,z,rem;
    while(scanf("%lld%lld",&n,&k)!=EOF)
    {
        z=n;
        c=0;
        while(n>=k)
        {
            rem=n%k;
            a=rem;
            b=n/k;
            c=c+b;
            n=a+b;
        }
        d=z+c;
        if(n>=k)
        {
            e=n/k;
            printf("%lld\n",d+e);
        }
        else
        {
            printf("%lld\n",d);
        }
    }
    return 0;
}