求条 60pts.悬2关

#include<bits/stdc++.h>
#define int long long
using namespace std;
int x,y,n,m,L;
int Exgcd(int a,int b,int &x,int &y){
	if(b==0){
		x=1;y=0;
		return a;
	}
	int t=Exgcd(b,a%b,x,y),t1=y;
	y=x-a/b*y;x=t1;
	return t;
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>x>>y>>n>>m>>L;
	int a=m-n,b=y-x,k=__gcd(a,L),X,Y;
	a=(a%L+L)%L,b=(b%L+L)%L;
	if(b%k!=0||m==n)cout<<"Impossible";
	else{
		Exgcd(a,L,X,Y);
		X*=(-b/k);
		cout<<(X%L+L)%L;
	}
	return 0;
}