> #include<stdio.h>
> #include<math.h>
> void main()
> {
> unsigned long x,y,m,n,L,s,s1,t=0,v;
> scanf("%ld%ld%ld%ld%ld",&x,&y,&m,&n,&L);
> if(m==n)
> 	printf("Impossible\n");
> else 
> 	{
> 	if((x-y)*(m-n)<0)
> 		s=abs(x-y);
> 	else
> 		s=L-abs(x-y);
> 	x=s;
> 	v=abs(m-n);
> 	while(1)
> 		{
> 		s1=s%v;/*错了吧如果s<v也要加一次时间的啊（比如相差1米，V=2米，还是得加一次的*/
> 		t=s/v+t;
> 		if(s1==0)
> 			{
> 			printf("%ld\n",t);
> 			break;
> 			}
> 		if((s1+L-x)%v==0)/*如果是几次后才出现循环呢*/
> 			{
> 			printf("Impossible\n");
> 			break;
> 			}
> 		s=s1+L;
> 		}
> 	} 
> }