> #include"stdio.h"
> int main()
> {  unsigned long  x,y,m,n,L,t;
>    scanf("%ld%ld%ld%ld%ld",&x,&y,&m,&n,&L);
>    if(x<y)
>    {  if(m==n) printf("Impossible\n");
>       else if(m>n)
> 	  {  t=(y-x)/(m-n);
>          if((float)t==(float)(y-x)/(float)(m-n))     printf("%ld\n",t);
> 	     else printf("Impossible\n");
> 	  }
>       else if(m<n)
> 	  {  t=(L+x-y)/(n-m);
>          if((float)t==(float)(L+x-y)/(float)(n-m))	  printf("%ld\n",t);
> 	     else printf("Impossible\n");
> 	  }
>    }
>    else if(x>y)
>    {  if(m==n) printf("Impossible\n");
>       else if(m<n)
> 	  {  t=(y-x)/(m-n);
>          if((float)t==(float)(y-x)/(float)(m-n))     printf("%ld\n",t);
> 	     else printf("Impossible\n");
> 	  }
>       else if(m>n)
> 	  {  t=(L-x+y)/(m-n);
>          if((float)t==(float)(L-x+y)/(float)(m-n))	  printf("%ld\n",t);
> 	     else printf("Impossible\n");
> 	  }
>    }
>    return 0;
> }