#include using namespace std; #define FOR(i,m,n) for(int i=(m);i<(n);++i) #define REP(i,n) FOR(i,0,n) using ll = long long; constexpr int INF = 0x3f3f3f3f; constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL; constexpr double EPS = 1e-8; constexpr int MOD = 998244353; // constexpr int MOD = 1000000007; constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1}; constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1}; constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1}; template inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; } template inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; } struct IOSetup { IOSetup() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << fixed << setprecision(20); } } iosetup; int main() { int n; cin >> n; vector> lr(n); for (auto& [l, r] : lr) cin >> l >> r; ranges::sort(lr); for (int i = n - 1; i >= 0; --i) { lr[i].second -= lr.front().first; lr[i].first -= lr.front().first; } int d = 0; REP(i, n) chmax(d, lr[i].first - i); for (auto& [l, r] : lr) { l = max(0, l - d); r -= d; if (r < l) { cout << 0 << '\n'; return 0; } } ranges::sort(lr); int lb = -1, ub = ranges::min(lr, {}, [](const auto& p) -> int { return p.second; }).second + 1; while (ub - lb > 1) { const int k = midpoint(lb, ub); bool is_valid = true; int id = 0; priority_queue, greater> que; REP(i, n) { while (id < n && lr[id].first - k <= i) que.emplace(lr[id++].second - k); if (que.empty() || que.top() < i) { is_valid = false; break; } que.pop(); } (is_valid ? lb : ub) = k; } cout << lb + 1 << '\n'; return 0; }