2520 10
2520 20
0 0

Case #1: 2520
Case #2: 2600

#include<stdio.h>
int main()
{
    __int64 x,k,i,j,t=0;
    while(scanf("%I64d%I64d",&x,&k)>0&&(x||k))
    {
        i=2;
        while(i<=k)
        {
            if(x%i!=0)
            {
                j=x/i+1; if(j<=i){x=j*k;break;}
                x=i*j;
            }
            else
            {
                j=x/i; if(j<=i){x=j*k;break;}
            }
            i++;
        }
        printf("Case #%I64d: %I64d\n",++t,x);
    }
}