#include <bits/stdc++.h>
using namespace std;
long long a[501000], add[501000];
const int S = 750;
struct _ {
  long long id;
  int val;
  bool operator<(const _ &ob) const { return id < ob.id; }
  bool operator==(const _ &ob) const { return id == ob.id; }
};
_ min_[750][750], max_[750][750];
int mintop[750], maxtop[750];
void rebuild(int x) {
  int i, cnt;
  for (i = x * S, cnt = 0; i < (x + 1) * S; ++i, ++cnt)
    min_[x][cnt] = (_){a[i], i + 1};
  stable_sort(min_[x], min_[x] + cnt);
  for (i = (x + 1) * S - 1, cnt = 0; i >= x * S; --i, ++cnt)
    max_[x][cnt] = (_){a[i], i + 1};
  stable_sort(max_[x], max_[x] + cnt);
  mintop[x] = unique(min_[x], min_[x] + cnt) - min_[x];
  maxtop[x] = unique(max_[x], max_[x] + cnt) - max_[x];
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, q;
  cin >> n >> q;
  int i;
  for (i = 1; i <= n; ++i) cin >> a[i];
  for (i = 0; i <= n / S; ++i) rebuild(i);
  int op, l, r, x, j;
  for (i = 1; i <= q; ++i) {
    cin >> op;
    if (op == 1) {
      cin >> l >> r >> x;
      if (l / S == r / S) {
        for (j = l; j <= r; ++j) a[j] += x;
        rebuild(l / S);
      } else {
        for (j = l; j / S == l / S; ++j) a[j] += x;
        rebuild(l / S);
        for (j = r / S * S; j <= r; ++j) a[j] += x;
        rebuild(r / S);
        for (j = l / S + 1; j < r / S; ++j) add[j] += x;
      }
    } else {
      cin >> x;
      int ans = -1;
      int l = 998244353, r = 0;
      for (j = 0; j <= n / S; ++j) {
        if (lower_bound(min_[j], min_[j] + mintop[j], (_){x - add[j], 0})->id ==
            x - add[j]) {
          l = min(l,
                  lower_bound(min_[j], min_[j] + mintop[j], (_){x - add[j], 0})
                      ->val);
          r = max(r,
                  lower_bound(max_[j], max_[j] + mintop[j], (_){x - add[j], 0})
                      ->val);
        }
      }
      ans = max(ans, r - l);
      cout << ans << '\n';
    }
  }
  return 0;
}
