poj 1061

#include<iostream>

using namespace std;

long long exgcd( long long a, long long b, long long &x, long long &y )
{
    if( b == 0 )
    {
        x = 1;
        y = 0;
        return a;
    }
     long long d = exgcd( b, a%b, x, y );
    long long temp = x;
    x = y;
    y = temp -(a/b)*y;
    return d;
}

int main()
{
    long long x, y, m, n, l;
    long long t, p;
    long long M, N;
    while (cin >> x>> y>> m>> n>> l)
    {
    M = exgcd( n-m, l, t, p );
    if( ( x - y )%M || (n == m) )
    {
        cout << "Impossible"<<endl;
    }else
    {
        N = l/M;
        t = t*( ( x - y )/M );
        t = ( t%N + N )%N;
        cout << t<< endl;

    }
    }

    return 0;

}