> #include<iostream.h>
> int main(){
> 	long int x,y,m,n,l,z,d,count;
> 	long f(long,long,long);
> 	cin>>x>>y>>m>>n>>l;
> 	z=(y-x)%l;
> 	if(z){
> 		if(m==n){
> 			count=-1;
> 		}
> 		else{
> 			if(n>m){
> 				z=l-z;
> 				d=(n-m)%l;
> 			}
> 			else 
> 				d=(m-n)%l;
> 			count=f(z,d,l);
> 		}
> 	}
> 	else
> 		count=0;
> 	if(count<0)cout<<"Impossible"<<endl;
> 	else cout<<count<<endl;
> 	return 0;
> }
> 
> long f(long z,long d,long l){
> 	long count,k;
> 	if(d){
> 		if(z%d==0){
> 			count=z/d;
> 			return count;
> 		}
> 		else {
> 			long d0=d;
> 			long z0=z;
> 			z=d0-z%d0;
> 			d=l%d0;			
> 			k=f(z,d,d0);
> 			if(k>0)
> 				count=(z0+k*l)/d0;
> 			else 
> 				return -1;
> 			return count;
> 		}
> 	}
> 	else 
> 		return -1;
> }