#include <bits/stdc++.h>   using namespace std;   int main() {     long long arr[100000], arr1[100000], n, x, z, co = 0, co1 = 0, k, m,                                                   fin = 1000000;     map<long long, long long> left;     map<long long, long long> right;     cin >> n;     if (n % 2 == 0)       k = n / 2;     else       k = (n / 2) + 1;     for (int i = 0; i < n; i++) {       cin >> x >> z;       if (x == z) {         if (left[x] == 0) {           arr[co++] = x;           left[x]++;         } else           left[x]++;       } else {         if (left[x] == 0) {           arr[co++] = x;           left[x]++;         } else           left[x]++;         if (right[z] == 0) {           arr1[co1++] = z;           right[z]++;         } else           right[z]++;       }     }     for (int i = 0; i < co; i++) {       m = 1000001;       if ((left[arr[i]] + right[arr[i]]) >= k) {         m = k - left[arr[i]];         if (m < 0) {           cout <<  0 ;           exit(0);         }       }       if (m < fin) {         fin = m;       }     }     if (fin == 1000000) {       for (int i = 0; i < co1; i++) {         if (right[arr1[i]] >= k) {           cout << k;           exit(0);         }       }     }     if (fin == 1000000)       cout <<  -1 ;     else       cout << fin;     return 0;   }   