#include <bits/stdc++.h>
using namespace std;
int main() {
 
    int t;
    cin>>t;
 
    while (t--) {
        int n;
        cin >> n;
        set<int>s;
        vector<int>st1;
        vector<int>st2;
        int a[n];
        /// scan
        for (int i = 0; i < n; i++) {
            cin>>a[i];
            s.insert(a[i]);
        }
        /// push to vector st1
        for(auto t: s) st1.push_back(t);
 
 
        int ans1=1; 
        int c1=0,c2=0;
        /// set 1
        for (int i = 0; i < st1.size()-1; ++i)
        {
            if(abs(st1[i]-st1[i+1])!=1) { ans1++;}
 
 
        }
 
        ///set 2
 
        for (int i = 0; i < n; ++i)
        {
            if(s.find(a[i])!=s.end())  {s.erase(s.find(a[i]));}
            else st2.push_back(a[i]);
        }
        int ans2;
        if(!st2.empty()) {
            ans2=1;
 
            sort(st2.begin(), st2.end());
 
 
            for (int i = 0; i < st2.size() - 1; ++i) {
 
                if(abs(st2[i]-st2[i+1])!=1) {ans2++; }
 
 
 
            }
 
        }
        else ans2=0;
 
 
 
        cout<<ans1+ans2<<endl;
 
 
 
 
 
    }
    return 0;
}

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10
6
2 2 3 4 3 1
5
11 8 7 10 9
6
1000000000 1000000000 1000000000 1000000000 1000000000 1000000000
8
1 1 4 4 2 3 2 3
6
1 2 3 2 3 4
7
10 11 11 12 12 13 13
7
8 8 9 9 10 10 11
8
4 14 5 15 6 16 7 17
8
5 15 6 14 8 12 9 11
5
4 2 2 3 4