func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   vector<int> v;   map<int, int> a, b;   int main() {     ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);     cin >> n;     int m = n / 2;     if (n % 2 != 0) {       m++;     }     for (int i = 1; i <= n; i++) {       int x, y;       cin >> x >> y;       a[x]++;       if (x != y) {         b[y]++;       }       v.push_back(x);       v.push_back(y);     }     int ans = 1e9;     for (int i = 0; i < 2 * n; i++) {       int cur = v[i];       int cnt = a[cur];       int need = max(0, m - cnt);       if (b[cur] >= need) {         ans = min(ans, need);       }     }     if (ans == 1e9) {       cout << -1;       return 0;     }     cout << ans;   }   