#line 1 "main.cpp"
#include<bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
//#pragma GCC target("avx,avx2")
//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pll = pair<ll,ll>;
using pii = pair<int,int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vul = vector<ull>;
using vpii = vector<pii>;
using vvpii = vector<vpii>;
using vpll = vector<pll>;
using vvpll = vector<vpll>;
using vs = vector<string>;
template<class T> using pq = priority_queue<T,vector<T>, greater<T>>;
#define overload4(_1, _2, _3, _4, name, ...) name
#define overload3(a,b,c,name,...) name
#define rep1(n) for (ll UNUSED_NUMBER = 0; UNUSED_NUMBER < (n); ++UNUSED_NUMBER)
#define rep2(i, n) for (ll i = 0; i < (n); ++i)
#define rep3(i, a, b) for (ll i = (a); i < (b); ++i)
#define rep4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define rrep1(n) for(ll i = (n) - 1;i >= 0;i--)
#define rrep2(i,n) for(ll i = (n) - 1;i >= 0;i--)
#define rrep3(i,a,b) for(ll i = (b) - 1;i >= (a);i--)
#define rrep4(i,a,b,c) for(ll i = (a) + (((b)-(a)-1) / (c) - (((b)-(a)-1) % (c) && (((b)-(a)-1) ^ c) < 0)) * (c);i >= (a);i -= c)
#define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__)
#define all1(i) begin(i) , end(i)
#define all2(i,a) begin(i) , begin(i) + a
#define all3(i,a,b) begin(i) + a , begin(i) + b
#define all(...) overload3(__VA_ARGS__, all3, all2, all1)(__VA_ARGS__)
#define sum(...) accumulate(all(__VA_ARGS__),0LL)
template<class T> bool chmin(T &a, const T &b){ if(a > b){ a = b; return 1; } else return 0; }
template<class T> bool chmax(T &a, const T &b){ if(a < b){ a = b; return 1; } else return 0; }
template<class T> auto min(const T& a){return *min_element(all(a));}
template<class T> auto max(const T& a){return *max_element(all(a));}
template<class... Ts> void in(Ts&... t);
#define INT(...) int __VA_ARGS__; in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define STR(...) string __VA_ARGS__; in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__; in(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__; in(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__; in(__VA_ARGS__)
#define VEC(type, name, size) vector<type> name(size); in(name)
#define VV(type, name, h, w) vector<vector<type>> name(h, vector<type>(w)); in(name)
ll intpow(ll a, ll b){ll ans = 1; while(b){if(b & 1) ans *= a; a *= a; b /= 2;} return ans;}
ll modpow(ll a, ll b, ll p){ ll ans = 1 % p; a %= p;if(a < 0) a += p;while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
bool is_clamp(ll val,ll low,ll high) {return low <= val && val < high;}
void Yes() {cout << "Yes\n";return;}
void No() {cout << "No\n";return;}
void YES() {cout << "YES\n";return;}
void NO() {cout << "NO\n";return;}
template <typename U,typename T>
U floor(U a, T b) {return a / b - (a % b && (a ^ b) < 0);}
// ceil(x,y) = floor(x+y-1,y)なのでx+y-1がoverflowする可能性あり
template <typename U,typename T>
U ceil(U x, T y) {return floor(x + y - 1, y);}
template <typename U,typename T>
T bmod(U x, T y) {return x - y * floor(x, y);}
template <typename U,typename T>
pair<U, T> divmod(U x, T y) {U q = floor(x, y);return {q, x - q * y};}
namespace IO{
#define VOID(a) decltype(void(a))
struct setting{ setting(){cin.tie(nullptr); ios::sync_with_stdio(false);fixed(cout); cout.precision(15);}} setting;
template<int I> struct P : P<I-1>{};
template<> struct P<0>{};
template<class T> void i(T& t){ i(t, P<3>{}); }
void i(vector<bool>::reference t, P<3>){ int a; i(a); t = a; }
template<class T> auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; }
template<class T> auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); }
template<class T, size_t... idx> void ituple(T& t, index_sequence<idx...>){in(get<idx>(t)...);}
template<class T> auto i(T& t, P<0>) -> VOID(tuple_size<T>{}){ituple(t, make_index_sequence<tuple_size<T>::value>{});} 
#undef VOID
}
#define unpack(a) (void)initializer_list<int>{(a, 0)...}
template<class... Ts> void in(Ts&... t){ unpack(IO :: i(t)); }
#undef unpack
constexpr long double PI = 3.141592653589793238462643383279L;
template <class F> struct REC {
    F f;
    REC(F &&f_) : f(forward<F>(f_)) {}
    template <class... Args> auto operator()(Args &&...args) const { return f(*this, forward<Args>(args)...); }};

constexpr int mod = 998244353;
//constexpr int mod = 1000000007;

#line 2 "library/graph/graph-template.hpp"
template <typename T> 
struct Edge {
	int from, to;
	T cost;
	Edge() = default;
	Edge(int _to, T _cost) : from(-1), to(_to), cost(_cost) {}
	Edge(int _from, int _to, T _cost) : from(_from), to(_to), cost(_cost) {}
	bool operator < (const Edge &a) const { return cost < a.cost; }
	bool operator > (const Edge &a) const { return cost > a.cost; }
    Edge &operator = (const int &x) {
        to = x;
        return *this;
    }
    operator int() const { return to; }
    friend ostream& operator<<(ostream &os, const Edge &edge) {
        return os << edge.to;
    }
};
 
template <typename T>
using Edges = vector<Edge<T>>;
template <typename T>
using Wgraph = vector<Edges<T>>;
using Ugraph = vector<vector<int>>;
Ugraph uinput(int N, int M = -1, bool is_directed = false, int origin = 1) {
    Ugraph g(N);
    if (M == -1) M = N - 1;
    while(M--) {
        int a,b;
        cin >> a >> b;
        a -= origin, b -= origin;
        g[a].push_back(b);
        if(!is_directed) g[b].push_back(a);
    }
    return g;
}
template <typename T>
Wgraph<T> winput(int N, int M = -1, bool is_directed = false,int origin = 1) {
    Wgraph<T> g(N);
    if (M == -1) M = N - 1;
    while(M--) {
        int a,b;
        T c;
        cin >> a >> b >> c;
        a -= origin, b -= origin;
        g[a].emplace_back(b,c);
        if(!is_directed) g[b].emplace_back(a,c);
    }
    return g;
}
#line 3 "library/graph/TopologicalSort.hpp"
template<typename T>
vector<int>TopologicalSort(T &g) {
    int N = g.size();
    vector<int> marked(N),tmp(N),v;
    auto visit = [&](auto &f,int i) -> bool {
        if(tmp[i] == 1) return false;
        if(marked[i] == 0) {
            tmp[i] = 1;
            for(auto &e:g[i]) {
                if(f(f,e) == false) return false;
            }
            marked[i] = 1;
            v.push_back(i);
            tmp[i] = 0;
        }
        return true;
    };
    for(int i = 0;i < N;i++) {
        if(marked[i] == 0) {
            if(visit(visit,i) == false) return vector<int>();
        }
    }
    reverse(v.begin(),v.end());
    return v;
}
#line 102 "main.cpp"
void solve() {
    INT(n,m);
    VEC(int,s,m);
    VEC(int,g,m);
    vi ord(m);
    iota(all(ord),0);
    sort(all(ord),[&](int i,int j){return g[i] < g[j];});
    rep(i,m-1) {
        if(g[ord[i]] < g[ord[i+1]]) {
            if(s[ord[i]] > s[ord[i+1]]) {
                cout << -1 << '\n';
                return;
            }
        }
        else {
            if(s[ord[i]] == s[ord[i+1]] && s[ord[i]] == g[ord[i]]);
            else {
                cout << -1 << '\n';
                return;
            }
        }
    }
    vi ns(m),ng(m);
    rep(i,m) {
        ns[i] = s[ord[i]];
        ng[i] = g[ord[i]];
    }
    s = move(ns),g = move(ng);
    vvi G(m);
    int ans = 0;
    rep(i,1,m) {
        if(s[i-1] > g[i-1] && s[i] > g[i]) {
            G[i-1].emplace_back(i);
        }
        else if(s[i-1] < g[i-1] && s[i] < g[i]) {
            G[i].emplace_back(i-1);
        }
        else if(s[i-1] < g[i-1] && s[i] > g[i]) {
            int h = g[i] - g[i-1];
            int d = s[i] - s[i-1];
            while(h < d) {
                ans++;
                h *= 2;
            }
            s[i-1] = g[i-1];
            s[i] = g[i];
        }
    }
    auto topo = TopologicalSort(G);
    auto calc = [&](int h,int d) {
        //debug(h,d);
        assert(h > d);
        int ret = 0;
        while(d > 0) {
            int nh = h / 2;
            ret++;
            d = max(0,d - nh);
            h = h - nh;
            //debug(d,h);
        };
        return ret;
    };
    rep(i,m) {
        int id = topo[i];
        //debug(s,g,id);
        if(s[id] < g[id]) {
            if(id == m - 1) {
                ans++;
            }
            else {
                ans += calc(s[id+1] - s[id],g[id] - s[id]);
            }
        }
        else if(s[id] > g[id]) {
            if(id == 0) {
                ans++;
            }
            else {
                ans += calc(s[id] - s[id-1],s[id] - g[id]);
            }
        }
        s[id] = g[id];
    }
    cout << ans << '\n';
}

int main() {
    int TT = 1;
    cin >> TT;
    while(TT--) solve();
}