#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define each(x, y) for (auto &x : y)
#define all(a) (a).begin(), (a).end()
#define bit(b) (1ll << (b))
#define uniq(v) (v).erase(unique(all(v)), (v).end())
#define rsort(v) sort(all(v)); reverse(all(v))

using namespace std;

using i32 = int;
using i64 = long long;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << '\n'; exit(0); }
inline void no() { cout << "No" << '\n'; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { return a / gcd(a, b) * b; }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }
template<typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template<typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template<typename T> inline void amax(T &x, T y) { if (x < y) x = y; }
template<typename T> inline void amin(T &x, T y) { if (x > y) x = y; }
template<typename T> inline T power(T x, i64 n) { T r = 1; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template<typename T> istream& operator>>(istream &is, vector<T> &v) { for (auto &x : v) is >> x; return is; }
template<typename T> ostream& operator<<(ostream &os, const vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }

struct SegmentTree {
  const int MAX = 2147483647;
  vi32 v, z;
  int n;
  SegmentTree(int sz) {
    n = 1;
    while (n < sz) n <<= 1;
    v.resize(n * 2, MAX);
    z.resize(n * 2, MAX);
  }
  inline void delegate(int k) {
    if (z[k] == MAX) return;
    v[k] = z[k];
    if (k < n) {
      z[k * 2 + 0] = z[k];
      z[k * 2 + 1] = z[k];
    }
    z[k] = MAX;
  }
  void update_node(int k) {
    v[k] = min(v[k * 2 + 0], v[k * 2 + 1]);
  }
  void update(int a, int b, int x, int k = 1, int l = 0, int r = -1) {
    if (r == -1) r = n;
    delegate(k);
    if (b <= l || r <= a) return;
    if (a <= l && r <= b) { z[k] = x; delegate(k); return; }
    update(a, b, x, k * 2 + 0, l, (l + r) / 2);
    update(a, b, x, k * 2 + 1, (l + r) / 2, r);
    update_node(k);
  }
  int query(int a, int b, int k = 1, int l = 0, int r = -1) {
    if (r == -1) r = n;
    delegate(k);
    if (b <= l || r <= a) return MAX;
    if (a <= l && r <= b) return v[k];
    int ret = MAX;
    amin(ret, query(a, b, k * 2 + 0, l, (l + r) / 2));
    amin(ret, query(a, b, k * 2 + 1, (l + r) / 2, r));
    return ret;
  }
};

void solve() {
  int n, q; cin >> n >> q;
  auto se = SegmentTree(n);
  rep(i, q) {
    int num; cin >> num;
    if (num == 0) {
      int s, t, x;
      cin >> s >> t >> x;
      t++;
      se.update(s, t, x);
    } else {
      int s, t;
      cin >> s >> t;
      t++;
      cout << se.query(s, t) << '\n';
    }
  }
}



Measured memory_bytes: 4868