#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
namespace io {
const int L = (1 << 20) + 1;
char buf[L], *S, *T, c;
char getchar() {
  if (__builtin_expect(S == T, 0)) {
    T = (S = buf) + fread(buf, 1, L, stdin);
    return (S == T ? EOF : *S++);
  }
  return *S++;
}
int inp() {
  int x = 0, f = 1;
  char ch;
  for (ch = getchar(); !isdigit(ch); ch = getchar())
    if (ch == '-') f = -1;
  for (; isdigit(ch); x = x * 10 + ch - '0', ch = getchar())
    ;
  return x * f;
}
unsigned inpu() {
  unsigned x = 0;
  char ch;
  for (ch = getchar(); !isdigit(ch); ch = getchar())
    ;
  for (; isdigit(ch); x = x * 10 + ch - '0', ch = getchar())
    ;
  return x;
}
long long inp_ll() {
  long long x = 0;
  int f = 1;
  char ch;
  for (ch = getchar(); !isdigit(ch); ch = getchar())
    if (ch == '-') f = -1;
  for (; isdigit(ch); x = x * 10 + ch - '0', ch = getchar())
    ;
  return x * f;
}
char B[25], *outs = B + 20, *outr = B + 20;
template <class T>
inline void print(register T a, register char x = 0) {
  if (x) *--outs = x, x = 0;
  if (!a)
    *--outs = '0';
  else
    while (a) *--outs = (a % 10) + 48, a /= 10;
  if (x) *--outs = x;
  fwrite(outs, outr - outs, 1, stdout);
  outs = outr;
}
};  // namespace io
using io ::inp;
using io ::inp_ll;
using io ::inpu;
using io ::print;
using i32 = int;
using i64 = long long;
using u8 = unsigned char;
using u32 = unsigned;
using u64 = unsigned long long;
using f64 = double;
using f80 = long double;
long long power(long long a, long long b, long long p) {
  if (!b) return 1;
  long long t = power(a, b / 2, p);
  t = t * t % p;
  if (b & 1) t = t * a % p;
  return t;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
template <class T>
inline void freshmin(T &a, const T &b) {
  if (a > b) a = b;
}
template <class T>
inline void freshmax(T &a, const T &b) {
  if (a < b) a = b;
}
const int MAXN = 100010;
const int MOD = 1000000007;
const f80 MI = f80(1) / MOD;
const int INF = 1000000000;
struct node {
  node *Lc, *Rc;
  int flag, set;
  long long sum, Lsum;
};
node *new_node() {
  node *it = new node;
  it->Lc = it->Rc = 0;
  it->flag = it->set = it->sum = it->Lsum = 0;
  return it;
}
void clear(node *p, int L, int R) {
  if (p->flag) {
    int m = (L + R) / 2;
    p->flag = 0;
    if (!p->Lc) p->Lc = new_node();
    if (!p->Rc) p->Rc = new_node();
    p->Lc->flag = p->Rc->flag = 1;
    p->Lc->set = p->Rc->set = p->set;
    p->Lc->sum = (long long)(m - L + 1) * p->set;
    p->Lc->Lsum = p->set >= 0 ? 0 : p->Lc->sum;
    p->Rc->sum = (long long)(R - m) * p->set;
    p->Rc->Lsum = p->set >= 0 ? 0 : p->Rc->sum;
  }
}
void update(node *p) {
  if (!p->Lc) p->Lc = new_node();
  if (!p->Rc) p->Rc = new_node();
  p->sum = p->Lc->sum + p->Rc->sum;
  p->Lsum = min(p->Lc->Lsum, p->Lc->sum + p->Rc->Lsum);
}
void modify(node *p, int L, int R, int x, int y, int v) {
  if (L == x && R == y) {
    p->flag = 1;
    p->set = v;
    p->sum = (long long)(R - L + 1) * v;
    p->Lsum = v >= 0 ? 0 : p->sum;
    return;
  }
  clear(p, L, R);
  int m = (L + R) / 2;
  if (y <= m) {
    if (!p->Lc) p->Lc = new_node();
    modify(p->Lc, L, m, x, y, v);
  } else if (x > m) {
    if (!p->Rc) p->Rc = new_node();
    modify(p->Rc, m + 1, R, x, y, v);
  } else {
    if (!p->Lc) p->Lc = new_node();
    if (!p->Rc) p->Rc = new_node();
    modify(p->Lc, L, m, x, m, v);
    modify(p->Rc, m + 1, R, m + 1, y, v);
  }
  update(p);
}
pair<double, long long> query(node *p, int L, int R, int x, int y,
                              long long v) {
  if (L == x && R == y) {
    if (p->Lsum + v > 0) return pair<double, long long>(-1, p->sum);
    if (L == R) return pair<double, long long>(L - (double)v / p->sum, p->sum);
    if (p->flag)
      return pair<double, long long>(L - (double)v / (p->sum / (R - L + 1)),
                                     p->sum);
    int m = (L + R) / 2;
    if (!p->Lc) p->Lc = new_node();
    if (!p->Rc) p->Rc = new_node();
    auto Lans = query(p->Lc, L, m, x, m, v);
    if (Lans.first > 0)
      return Lans;
    else {
      auto Rans = query(p->Rc, m + 1, R, m + 1, y, Lans.second + v);
      return pair<double, long long>(Rans.first, Lans.second + Rans.second);
    }
  }
  clear(p, L, R);
  int m = (L + R) / 2;
  if (y <= m) {
    if (!p->Lc) p->Lc = new_node();
    return query(p->Lc, L, m, x, y, v);
  } else if (x > m) {
    if (!p->Rc) p->Rc = new_node();
    return query(p->Rc, m + 1, R, x, y, v);
  } else {
    if (!p->Lc) p->Lc = new_node();
    if (!p->Rc) p->Rc = new_node();
    auto Lans = query(p->Lc, L, m, x, m, v);
    if (Lans.first > 0)
      return Lans;
    else {
      auto Rans = query(p->Rc, m + 1, R, m + 1, y, Lans.second + v);
      return pair<double, long long>(Rans.first, Lans.second + Rans.second);
    }
  }
}
int main() {
  int q = inp();
  map<int, int> H;
  int L = 1, R = 1000000010;
  H[L - 1] = H[R + 1] = 0;
  node *root = new_node();
  while (q--) {
    int t = inp();
    if (t == 1) {
      int x = inp();
      int y = inp();
      H[x] = y;
      auto it = H.find(x);
      ++it;
      modify(root, L, R - 1, x, min(it->first, R) - 1, y);
    } else if (t == 2) {
      int x = inp();
      auto it = H.find(x);
      auto ity = it;
      ++ity;
      auto itx = it;
      --itx;
      modify(root, L, R - 1, x, min(ity->first, R) - 1, itx->second);
      H.erase(x);
    } else if (t == 3) {
      int x = inp();
      int y = inp();
      int v = inp();
      if (v == 0)
        printf("%d\n", x);
      else {
        auto it = H.lower_bound(x);
        x = it->first;
        if (x >= y)
          puts("-1");
        else {
          auto ans = query(root, L, R - 1, x, y - 1, v);
          if (ans.first < 0)
            puts("-1");
          else
            printf("%.8f\n", ans.first);
        }
      }
    }
  }
  return 0;
}
