#include <bits/stdc++.h>
using namespace std;
int main(){
  int a, b, c, d, m;
  cin >> a >> b >> c >> d >> m;
  if ((a + c) / m != (b + d) / m){
    cout << m - 1 << endl;
  } else {
    cout << (b + d) % m << endl;
  }
}