Problem: You are given array a with n integers and m queries. The i-th query is given with three integers li, ri, xi.

For the i-th query find any position pi (li ≤ pi ≤ ri) so that api ≠ xi.

Input

The first line contains two integers n, m (1 ≤ n, m ≤ 2·105) — the number of elements in a and the number of queries.

The second line contains n integers ai (1 ≤ ai ≤ 106) — the elements of the array a.

Each of the next m lines contains three integers li, ri, xi (1 ≤ li ≤ ri ≤ n, 1 ≤ xi ≤ 106) — the parameters of the i-th query.

Output

Print m lines. On the i-th line print integer pi — the position of any number not equal to xi in segment [li, ri] or the value  - 1 if there is no such number.

Examples

Input

6 4
1 2 1 1 3 5
1 4 1
2 6 2
3 4 1
3 4 2


Output

2
6
-1
4

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const double pi = 2 * acos(0.0);
template <typename T>
T Sqr(T x) {
  T n = x * x;
  return n;
}
template <typename T>
T Pow(T B, T P) {
  if (P == 0) return 1;
  if (P & 1)
    return B * Pow(B, P - 1);
  else
    return Sqr(Pow(B, P / 2));
}
template <typename T>
T Abs(T a) {
  if (a < 0)
    return -a;
  else
    return a;
}
template <typename T>
T Gcd(T a, T b) {
  if (a < 0) return Gcd(-a, b);
  if (b < 0) return Gcd(a, -b);
  return (b == 0) ? a : Gcd(b, a % b);
}
template <typename T>
T Lcm(T a, T b) {
  if (a < 0) return Lcm(-a, b);
  if (b < 0) return Lcm(a, -b);
  return a * (b / Gcd(a, b));
}
template <typename T>
T Exgcd(T a, T b, T &x, T &y) {
  if (a < 0) {
    T d = Exgcd(-a, b, x, y);
    x = -x;
    return d;
  }
  if (b < 0) {
    T d = Exgcd(a, -b, x, y);
    y = -y;
    return d;
  }
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  } else {
    T d = Exgcd(b, a % b, x, y);
    T t = x;
    x = y;
    y = t - (a / b) * y;
    return d;
  }
}
template <typename T>
T BigMod(T b, T p, T m) {
  if (p == 0) return 1;
  if (p % 2 == 0) {
    T s = BigMod(b, p / 2, m);
    return ((s % m) * (s % m)) % m;
  }
  return ((b % m) * (BigMod(b, p - 1, m) % m)) % m;
}
template <typename T>
T ModInvPrime(T b, T m) {
  return BigMod(b, m - 2, m);
}
template <typename T>
T ModInvNotPrime(T a, T m) {
  T x, y;
  Exgcd(a, m, x, y);
  x %= m;
  if (x < 0) x += m;
  return x;
}
template <typename T>
typename std::vector<T>::iterator Insert_sorted(std ::vector<T> &vec,
                                                T const &item) {
  return vec.insert(std::upper_bound(vec.begin(), vec.end(), item), item);
}
template <typename T>
inline string ToBinary(T n) {
  string r;
  while (n != 0) {
    r = (n % 2 == 0 ? "0" : "1") + r;
    n >>= 1;
  }
  return r;
}
long long BinaryToDecimal(string s) {
  int len = s.size();
  long long n = 0, p = 1;
  for (int i = len - 1; i >= 0; i--, p *= 2) n += p * (s[i] - '0');
  return n;
}
char Uplowch(char ch) {
  if (ch >= 'A' && ch <= 'Z') ch += 32;
  return ch;
}
char Lowupch(char ch) {
  if (ch >= 'a' && ch <= 'z') ch -= 32;
  return ch;
}
bool Isalpha(char ch) {
  if ((ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z')) return true;
  return false;
}
int Strtoint(string str) {
  stringstream ss(str);
  int x = 0;
  ss >> x;
  return x;
}
string Intostr(int x) {
  stringstream ss;
  ss << x;
  string str = ss.str();
  return str;
}
vector<string> Linetostr(string str) {
  string s;
  vector<string> v;
  istringstream is(str);
  while (is >> s) v.push_back(s);
  return v;
}
template <typename T>
void Print(T ar[], int a, int b) {
  for (int i = a; i + 1 <= b; i++) cout << ar[i] << " ";
  cout << ar[b] << "\n";
}
template <typename T>
void Print(T ar[], int n) {
  for (int i = 0; i + 1 < n; i++) cout << ar[i] << " ";
  cout << ar[n - 1] << "\n";
}
template <typename T>
void Print(const vector<T> &v) {
  for (int i = 0; i + 1 < v.size(); i++) cout << v[i] << " ";
  cout << v.back() << "\n";
}
struct SegmentTree {
  vector<pair<int, int>> seg;
  vector<long long> lazy;
  vector<int> ar;
  void Init(int N) {
    seg.assign(N << 2, {});
    lazy.assign(N << 2, 0);
  }
  void Init(const vector<int> &s) {
    Init(s.size() + 1);
    ar = s;
  }
  void PushDown(int cur, int left, int right) {
    if (left != right) {
      lazy[cur << 1] += lazy[cur];
      lazy[cur << 1 | 1] += lazy[cur];
    }
    lazy[cur] = 0;
  }
  pair<int, int> Merge(pair<int, int> x, pair<int, int> y) {
    return make_pair(max(x.first, y.first), min(x.second, y.second));
  }
  void Build(int cur, int left, int right) {
    lazy[cur] = 0;
    if (left == right) {
      seg[cur] = {ar[left], ar[left]};
      return;
    }
    int mid = (left + right) >> 1;
    Build(cur << 1, left, mid);
    Build(cur << 1 | 1, mid + 1, right);
    seg[cur] = Merge(seg[cur << 1], seg[cur << 1 | 1]);
  }
  void Update(int cur, int left, int right, int pos, long long val) {
    Update(cur, left, right, pos, pos, val);
  }
  void Update(int cur, int left, int right, int l, int r, long long val) {
    if (l > right || r < left) return;
    if (left >= l && right <= r) {
      lazy[cur] = val;
      PushDown(cur, left, right);
      return;
    }
    int mid = (left + right) >> 1;
    Update(cur << 1, left, mid, l, r, val);
    Update(cur << 1 | 1, mid + 1, right, l, r, val);
    seg[cur] = Merge(seg[cur << 1], seg[cur << 1 | 1]);
  }
  pair<int, int> Query(int cur, int left, int right, int l, int r) {
    if (l > right || r < left) return make_pair(-2147483647, 2147483647);
    if (left >= l && right <= r) return seg[cur];
    int mid = (left + right) >> 1;
    pair<int, int> p1 = Query(cur << 1, left, mid, l, r);
    pair<int, int> p2 = Query(cur << 1 | 1, mid + 1, right, l, r);
    return Merge(p1, p2);
  }
} T;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, m;
  cin >> n >> m;
  vector<int> v(n + 1);
  map<int, vector<int>> mp;
  for (int i = 1; i <= n; i++) {
    cin >> v[i];
    mp[v[i]].emplace_back(i);
  }
  T.Init(v);
  T.Build(1, 1, n);
  while (m--) {
    int l, r, x;
    cin >> l >> r >> x;
    pair<int, int> ans = T.Query(1, 1, n, l, r);
    if (ans.first != x) {
      cout << *lower_bound(mp[ans.first].begin(), mp[ans.first].end(), l)
           << "\n";
    } else if (ans.second != x) {
      cout << *lower_bound(mp[ans.second].begin(), mp[ans.second].end(), l)
           << "\n";
    } else {
      cout << "-1\n";
    }
  }
  return 0;
}