func_code_string: #include <bits/stdc++.h>   using namespace std;   void __print(int x) { cerr << x; }   void __print(long x) { cerr << x; }   void __print(long long x) { cerr << x; }   void __print(unsigned x) { cerr << x; }   void __print(unsigned long x) { cerr << x; }   void __print(unsigned long long x) { cerr << x; }   void __print(float x) { cerr << x; }   void __print(double x) { cerr << x; }   void __print(long double x) { cerr << x; }   void __print(char x) { cerr <<      << x <<     ; }   void __print(const char *x) { cerr <<     << x <<    ; }   void __print(const string &x) { cerr <<     << x <<    ; }   void __print(bool x) { cerr << (x ?  true  :  false ); }   template <typename T, typename V>   void __print(const pair<T, V> &x) {     cerr <<  { ;     __print(x.first);     cerr <<  , ;     __print(x.second);     cerr <<  } ;   }   template <typename T>   void __print(const T &x) {     int f = 0;     cerr <<  { ;     for (auto &i : x) cerr << (f++ ?  ,  :   ), __print(i);     cerr <<  } ;   }   void _print() { cerr <<  ] n ; }   template <typename T, typename... V>   void _print(T t, V... v) {     __print(t);     if (sizeof...(v)) cerr <<  ,  ;     _print(v...);   }   template <typename T>   void Print(T a[], T n) {     for (int i = 0; i < n; i++) {       cout << a[i] <<    ;     }     cout << endl;   }   void solve() {     int n;     cin >> n;     string s, t;     cin >> s >> t;     if (s == t) {       cout << 0 <<   n ;       return;     }     int same1 = 0, diff1 = 0, same = 0;     for (int i = 0; i < n; i++) {       if (s[i] == t[i]) {         same++;         if (s[i] ==  1 ) same1++;       } else {         if (s[i] ==  1 ) diff1++;       }     }     int diff = n - same;     if (same == n) {       cout << 0 <<   n ;       return;     }     int ans = INT_MAX;     if (same1 - 1 == same - same1) {       ans = min(ans, same);     }     if (diff1 == diff - diff1) {       ans = min(ans, diff);     }     if (ans != INT_MAX)       cout << ans <<   n ;     else       cout << -1 <<   n ;   }   void solve1() {     int n;     cin >> n;     string s, t;     cin >> s >> t;     if (s == t) {       cout << 0 <<   n ;       return;     }     int same1 = 0, diff1 = 0, same = 0;     for (int i = 0; i < n; i++) {       if (s[i] == t[i]) {         same++;         if (s[i] ==  1 ) same1++;       } else {         if (s[i] ==  1 ) diff1++;       }     }     int diff = n - same;     int ans = INT_MAX;     if (diff % 2 == 0) {       int one = (diff + 1) / 2;       if (diff1 == one) {         ans = min(ans, diff);       }     }     if (same % 2 != 0) {       int one = (same + 1) / 2;       if (same1 == one) {         ans = min(ans, same);       }     }     if (ans == INT_MAX)       cout << -1 <<   n ;     else       cout << ans <<   n ;   }   signed main() {     ios_base::sync_with_stdio(false), cin.tie(NULL);     int t;     cin >> t;     while (t--) solve1();   }   