#include <bits/stdc++.h>   using namespace std;   int main() {     int long long l1, l2, r1, r2, k, ans, l, r;     cin >> l1;     cin >> r1;     cin >> l2;     cin >> r2;     cin >> k;     l = max(l1, l2);     r = min(r1, r2);     if (r - l < 0) {       cout << 0 << endl;       return 0;     }     ans = r - l + 1;     if (k >= l && k <= r) ans--;     cout << ans << endl;   }   