#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")


template <class T> void bAdd(vector<T> &bit, int pos, const T &val) {
  const int bitN = bit.size();
  for (int x = pos; x < bitN; x |= x + 1) bit[x] += val;
}
template <class T> T bSum(const vector<T> &bit, int pos) {
  T ret = 0;
  for (int x = pos; x > 0; x &= x - 1) ret += bit[x - 1];
  return ret;
}
template <class T> T bSum(const vector<T> &bit, int pos0, int pos1) {
  return bSum(bit, pos1) - bSum(bit, pos0);
}

// min pos s.t. pred(sum of [0, pos))
//   assume pred(sum of [0, pos)) is non-decreasing
template <class T, class Pred>
int bBinarySearch(const vector<T> &bit, Pred pred) {
  if (pred(T(0))) return 0;
  const int bitLen = bit.size();
  int pos = 0;
  T sum = 0;
  for (int e = 31 - __builtin_clz(bitLen); e >= 0; --e) {
    const int x = (pos | 1 << e) - 1;
    if (x < bitLen && !pred(sum + bit[x])) {
      pos |= 1 << e;
      sum += bit[x];
    }
  }
  return pos + 1;
}


int N, Q;
vector<int> A;
vector<int> X, K, Y;

namespace brute {
vector<int> run() {
  auto as = A;
  vector<int> bs(N);
  vector<int> app(N + 1, -1);
  vector<int> ans(Q, -1);
  for (int q = 0; q < Q; ++q) {
    as[X[q]] = K[q];
    int mex = 0;
    for (int i = 0; i < N; ++i) {
      if (as[i] == -1) {
        for (; app[mex] == q; ++mex) {}
        bs[i] = mex;
      } else {
        bs[i] = as[i];
      }
      if (bs[i] >= 0) {
        app[bs[i]] = q;
      }
    }
    ans[q] = bs[Y[q]];
  }
  return ans;
}
}  // brute

namespace sub2 {
vector<int> run() {
  int I0;
  for (I0 = 0; I0 < N && A[I0] == -2; ++I0) {}
  vector<int> bit(N + 1, 0);
  for (int x = 0; x <= N; ++x) bAdd(bit, x, +1);
  auto as = A;
  vector<int> freq(N + 1, 0);
  vector<int> ans(Q, -1);
  for (int q = 0; q < Q; ++q) {
    {
      int &a = as[X[q]];
      if (a >= 0) if (!--freq[a]) bAdd(bit, a, +1);
      a = K[q];
      if (a >= 0) if (!freq[a]++) bAdd(bit, a, -1);
    }
    if (Y[q] < I0) {
      ans[q] = as[Y[q]];
    } else {
      ans[q] = bBinarySearch(bit, [&](int sum) -> bool {
        return (sum > Y[q] - I0);
      }) - 1;
    }
  }
  return ans;
}
}  // sub2

int main() {
  for (; ~scanf("%d%d", &N, &Q); ) {
    A.resize(N);
    for (int i = 0; i < N; ++i) {
      scanf("%d", &A[i]);
      --A[i];
    }
    X.resize(Q);
    K.resize(Q);
    Y.resize(Q);
    for (int q = 0; q < Q; ++q) {
      scanf("%d%d%d", &X[q], &K[q], &Y[q]);
      --X[q];
      --K[q];
      --Y[q];
    }
    
    bool spe2 = true;
    for (int i = 0; i < N - 1; ++i) spe2 = spe2 && (A[i] <= A[i + 1]);
    
    vector<int> ans;
    if (spe2) {
      ans = sub2::run();
    } else {
      ans = brute::run();
    }
    for (int q = 0; q < Q; ++q) {
      printf("%d\n", ans[q] + 1);
    }
  }
  return 0;
}