> #include<stdio.h>
> #include<iostream>
> #include<string.h>
> using namespace std;
> long long x,y,e;
> void gcd(long long a,long long b,long long c)
> {
>      if(a==0)
>      {x=0,y=c/b,e=b;return;}
>      gcd(b%a,a,c);
>      long long t=y;
>      y=x,x=t-(b/a)*x;    
> }
> int main()
> {
>     long long a,b,m,n,l;
>     scanf("%I64d%I64d%I64d%I64d%I64d",&a,&b,&m,&n,&l);
>     if(m<n)swap(a,b),swap(m,n);
>     gcd(m-n,l,b-a);
>     if((b-a)%e!=0)printf("Impossible\n");
>     else
>     {
>         if(e!=0)
>         {
>         long long d=(m-n)*l/e;
>         if(x<1){x+=(-x+1)/(d/(m-n))*d/(m-n);if(x<1)x+=d/(m-n);}
>         else x-=(x-1)/(d/(m-n))*(d/(m-n));
>         }
>         printf("%I64d\n",x);
>     }
>     
>     return 0;
> }
m=n啊