#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")


/*
  problem
    query
      0 x h: add h to position x (which was empty)
      1 L R H: find distance from values in [L, R] to H
*/

constexpr int INF = 1001001001;

int main() {
  for (int numCases; ~scanf("%d", &numCases); ) { for (int caseId = 1; caseId <= numCases; ++caseId) {
    int N, Q;
    scanf("%d%d", &N, &Q);
    
    int segN;
    for (segN = 1; segN < N; segN <<= 1) {}
    vector<set<int>> seg(segN << 1);
    
    for (; Q--; ) {
      int O;
      scanf("%d", &O);
      if (O == 0) {
        int X, H;
        scanf("%d%d", &X, &H);
        --X;
        for (int a = segN + X; a; a >>= 1) {
          seg[a].insert(H);
        }
      } else if (O == 1) {
        int L, R, H;
        scanf("%d%d%d", &L, &R, &H);
        ++R;
        int ans = INF;
        auto check = [&](int a) -> void {
          auto it = seg[a].lower_bound(H);
          if (it != seg[a].end()) {
            chmin(ans, *it - H);
          }
          if (it != seg[a].begin()) {
            --it;
            chmin(ans, H - *it);
          }
        };
        for (int a = segN + L, b = segN + R; a < b; a >>= 1, b >>= 1) {
          if (a & 1) check(a++);
          if (b & 1) check(--b);
        }
        printf("%d\n", (ans < INF) ? ans : -1);
      } else {
        assert(false);
      }
    }
  }
#ifndef LOCAL
  break;
#endif
  }
  return 0;
}