def main():
    def cal(S, T, l, r):
        l -= 1
        r += 1
        rep = 0
        if T[0] < S[0]:
            if l == -1:
                rep += 1
            else:
                x = S[0]-l
                y = T[0]-l
                #print(x, y, 0)
                while y < x:
                    rep += 1
                    x = (x+1)//2
            S[0] = T[0]
        if T[-1] > S[-1]:
            if r == -1:
                rep += 1
            else:
                x = r-S[-1]
                y = r-T[-1]
                #print(x, y, 1)
                while y < x:
                    rep += 1
                    x = (x+1)//2
            S[-1] = T[-1]
        for i in range(len(S)-1):
            if S[i] < T[i] and T[i+1] < S[i+1]:
                l0, r0, l1, r1 = S[i], S[i+1], T[i], T[i+1]
                c = min(l1-l0, r0-r1)
                f = 1
                le = r1-l1
                i = 0
                m = (c+le-1)//le
                if l1-l0 <= r0-r1:
                    f = 0
                while l0 < l1 or r1 < r0:
                    rep += 1
                    f1 = 0
                    if m >> i & 1:
                        f1 = 1
                    if f ^ f1:
                        l1 = max(l0, 2*l1-r1)
                    else:
                        r1 = min(r0, 2*r1-l1)
                    i += 1
            elif S[i] < T[i]:
                x = T[i+1]-S[i]
                y = T[i+1]-T[i]
                #print(x, y, 2)
                while y < x:
                    rep += 1
                    x = (x+1)//2
            elif T[i+1] < S[i+1]:
                x = S[i+1]-T[i]
                y = T[i+1]-T[i]
                #print(x, y, 3)
                while y < x:
                    rep += 1
                    x = (x+1)//2
        return rep
    n, m = list(map(int, input().split()))
    A = list(map(int, input().split()))
    B = list(map(int, input().split()))
    C = [(a, b) for a, b in zip(A, B)]
    C.sort()
    T = []
    S = []
    l = 0
    ans = 0
    for i in range(m):
        if C[i][0] == C[i][1]:
            if T:
                #print(S)
                #print(T)
                if sorted(T) == T and len(T) == len(set(T)) and l <= T[0] and T[-1] < C[i][1]:
                    ans += cal(S, T, l, C[i][1]-1)
                    pass
                else:
                    return -1
            l = C[i][1]+1
            T = []
            S = []
            continue
        T.append(C[i][1])
        S.append(C[i][0])
    if T:
        #print(S)
        #print(T)
        if sorted(T) == T and len(T) == len(set(T)) and l <= T[0]:
            ans += cal(S, T, l, -2)
            return ans
    else:
        return ans
    return -1

for _ in range(int(input())):
    print(main())