#include <bits//stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace std; using namespace __gnu_pbds; typedef tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset; #define ll long long #define iloop(m, h) for (auto i = m; i != h; i += (m < h ? 1 : -1)) #define jloop(m, h) for (auto j = m; j != h; j += (m < h ? 1 : -1)) #define kloop(m, h) for (auto k = m; k != h; k += (m < h ? 1 : -1)) #define pll pair<ll, ll> #define INF 1000000000000000 #define MOD1 1000000007 #define MOD2 998244353 #define MOD3 1000000009 int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); ll n; cin >> n; double a[n], b[n]; iloop(0, n) cin >> a[i] >> b[i]; sort(a, a+n); sort(b, b+n); double cans = 0, ca1 = 0, ca2 = 0, cv = 0; ll cn1 = n-1, cn2 = n-1; iloop(0, 2*n) { cv++; if (cn1 == -1 || ca1 > ca2) { ca2 += b[cn2]; cn2--; } else { ca1 += a[cn1]; cn1--; } cans = max(cans, min(ca1, ca2) - cv); } cout << fixed << setprecision(4) << cans; }