#include<stdio.h>
void main()
{
long x,y,m,n,l,i,d,k;
scanf("%ld %ld %ld %ld %ld",&x,&y,&m,&n,&l);
if(m==n)
printf("Impossible\n");
else
{for(i=1;i<=l;i++)
    {k=x-y+(m-n)*i;
       if((k%l)==0)
	 {d=1;printf("%ld\n",i);break;}
        else d=0;
      }
if(d==0)
printf("Impossible\n");}
}