#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
#include <queue>
#include <map>
#include <cmath>
#include <iomanip>

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;
  }
  return 0;
}