> #include<iostream>
> #include<stdio.h>
> #include<cmath>
> using namespace std;
> long long int gcd(long long int a,long long int b,long long int &x,long long int &y){
>     if (b==0){
>         x=1,y=0;
>         return a;
>     }
>     int q=gcd(b,a%b,y,x);
>     y-=a/b*x;
>     return q;
> }
> int main()
> {
>     long long int x,y,m,n,l;
>     while(scanf("%I64d%I64d%I64d%I64d%I64d",&x,&y,&m,&n,&l)!=EOF)
>     {
>         long long int a=(n-m),c=(x-y),x0,y0;
>         long long int g=gcd(a,l,x0,y0);
>         if(n==m||c%g!=0)
>         {
>           cout<<"Impossible"<<endl;
>         }else
>         {
>             x0=x0*(c/g);
>             int b=l/g;
>             x0=(x0%b+b)%b;
>             cout<<x0<<endl;
>         }
>     }
>     return 0;
> }
> 
> 
> 9 8 7 6 4
> 
> -1