#ifndef LOCAL
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target ("avx")
#endif

#include <vector>
#include <set>
#include <map>
#include <tuple>
#include <queue>
#include <stack>
#include <bitset>
#include <functional>
#include <algorithm>
#include <utility>
#include <numeric>
#include <iostream>
#include <cmath>
#include <cassert>
#include <cstring>

using namespace std;

using ll = long long;
using VI = vector<int>;
using VVI = vector<vector<int>>;
using VLL = vector<ll>;
using VVLL = vector<vector<ll>>;
using VB = vector<bool>;
using PII = pair<int, int>;
using PLL = pair<ll, ll>;
template <typename T>
using minheap = priority_queue<T, vector<T>, greater<T>>;
const int INF = 1000000007;
const ll INF_LL = 1'000'000'000'000'000'007;

#define __overload3(_1, _2, _3, name,...) name
#define rep(...) __overload3(__VA_ARGS__, repFromUntil, repUntil, repeat)(__VA_ARGS__)
#define repeat(times) repFromUntil(_name##__LINE__, 0, times)
#define repUntil(name, times) repFromUntil(name, 0, times)
#define repFromUntil(name, from, until) for (int name = from, name##__until = (until); name < name##__until; name++)
#define repr(...) __overload3(__VA_ARGS__, reprFromUntil, reprUntil, repeat)(__VA_ARGS__)
#define reprUntil(name, times) reprFromUntil(name, 0, times)
#define reprFromUntil(name, from, until) for (int name = until - 1, name##__from = (from); name >= name##__from; name--)

#define EXIT(out) do { OUT(out); exit(0); } while (0)

#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define fs first
#define sn second

#ifdef LOCAL
#define debug(v) do {debugos << "L" << __LINE__ << " " << #v << " > ";debugos<<(v)<<newl;} while (0)
#define debugv(v) do {debugos << "L" << __LINE__ << " " << #v << " > ";for(auto e:(v)){debugos<<e<<" ";}debugos<<newl;} while (0)
#define debuga(m,w) do {debugos << "L" << __LINE__ << " " << #m << " > ";for(int x=0;x<(w);x++){debugos<<(m)[x]<<" ";}debugos<<newl;} while (0)
#define debugaa(m,h,w) do {debugos << "L" << __LINE__ << " " << #m << " > \n";for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){debugos<<(m)[y][x]<<" ";}debugos<<newl;}} while (0)
#else
#define debug(v) do {v;} while (0)
#define debugv(v) do; while (0)
#define debuga(m,w) do; while (0)
#define debugaa(m,h,w) do; while (0)
#endif

#define newl "\n"
constexpr int dr[] = {1,-1,0,0};  // LRUD
constexpr int dc[] = {0,0,1,-1};

bool inside(int r, int c, int H, int W) {
  return 0 <= r and r < H and 0 <= c and c < W;
}

template <typename T> bool chmin(T& var, T x) {
  if (var > x) {
    var = x;
    return true;
  } else return false;
}

template <typename T> bool chmax(T& var, T x) {
  if (var < x) {
    var = x;
    return true;
  } else return false;
}

template <typename T> int sgn(T val) { return (T(0) < val) - (val < T(0)); }

ll power(ll e, int t, ll mod = INF_LL) {
  ll res = 1;
  while (t) {
    if (t&1) res = (res * e) % mod;
    t >>= 1;
    e = (e * e) % mod;
  }
  return res;
}

template <typename T> T divceil(T m, T d) {
  assert(m >= 0 and d > 0);
  return (m+d-1)/d;
}

template<typename T>
vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }

template<typename... Ts>
auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v(ts...))>(a, make_v(ts...));
}

string operator*(const string& s, int times) {
  string res = "";
  rep(times) res += s;
  return res;
}

class MyScanner {
public:
  int offset = 0;
  char nc(){
#ifdef LOCAL
    return getchar();
#else
    static char buf[100000],*L=buf,*R=buf;
    return L==R&&(R=(L=buf)+fread(buf,1,100000,stdin),L==R)?EOF:*L++;
#endif
  }
  template <typename T> void input_integer(T& var) {
    var = 0; T sign = 1;
    int cc = nc();
    for (; cc<'0' || '9'<cc; cc = nc())
      if (cc == '-') sign = -1;
    for (; '0' <= cc && cc <= '9'; cc = nc())
      var = (var << 3) + (var << 1) + cc - '0';
    var = var * sign; var += offset;
  }
  int c() { char c; while (c = nc(), c == ' ' or c == '\n'); return c; }
  MyScanner& operator>>(char& var) { var = c(); return *this; }
  MyScanner& operator>>(int& var) { input_integer<int>(var); return *this; }
  MyScanner& operator>>(ll& var) { input_integer<ll>(var); return *this; }
  MyScanner& operator>>(string& var) {
    var = ""; int cc = nc();
    for (; !isvisiblechar(cc); cc = nc());
    for (; isvisiblechar(cc); cc = nc())
      var.push_back(cc);
    return *this;
  }
  template <typename T>
  operator T() { T x; *this >> x; return x; }
  template <typename T>
  void operator()(T &t) { *this >> t; }
  template <typename T, typename... Ts>
  void operator()(T &t, Ts &...ts) { *this >> t; this->operator()(ts...); }
  template <typename Iter>
  void iter(Iter first, Iter last) { while (first != last) *this >> *first, first++; }
  VI vi(int n) { VI res(n); iter(all(res)); return res; }
  VVI vvi(int n, int m) { VVI res(n); rep(i, n) res[i] = vi(m); return res; }
  VLL vll(int n) { VLL res(n); iter(all(res)); return res; }
  VVLL vvll(int n, int m) { VVLL res(n); rep(i, n) res[i] = vll(m); return res; }
  template <typename T>
  vector<T> v(int n) { vector<T> res(n); iter(all(res)); return res; }
private:
  int isvisiblechar(int c) { return 0x21 <= c && c <= 0x7E; }
} IN, IN1{-1};

class MyPrinter {
public:
  template <typename T>
  void output_integer(T var) {
    if (var == 0) { putchar('0'); return; }
    if (var < 0) putchar('-'), var = -var;
    char stack[32]; int stack_p = 0;
    while (var) stack[stack_p++] = '0' + (var % 10), var /= 10;
    while (stack_p) putchar(stack[--stack_p]);
  }
  MyPrinter& operator<<(char c) { putchar(c); return *this; }
  MyPrinter& operator<<(double x) { printf("%.10f\n", x); return *this; }
  template <typename T> MyPrinter& operator<<(T var) { output_integer<T>(var); return *this; }
  MyPrinter& operator<<(char* str_p) { while (*str_p) putchar(*(str_p++)); return *this; }
  MyPrinter& operator<<(const char* str_p) { while (*str_p) putchar(*(str_p++)); return *this; }
  MyPrinter& operator<<(const string& str) {
    const char* p = str.c_str();
    const char* l = p + str.size();
    while (p < l) putchar(*p++);
    return *this;
  }
  template <typename T>
  void operator()(T x) { *this << x << newl; }
  template <typename T, typename... Ts>
  void operator()(T x, Ts ...xs) { *this << x << " "; this->operator()(xs...); }
  template <typename Iter>
  void iter(Iter s, Iter t) {
    if (s == t) *this << "\n";
    else {
      for (; s != t; s++) {
        *this << *s << " \n"[next(s, 1) == t];
      }
    }
  }
  template <typename Range>
  void range(const Range& r) { iter(begin(r), end(r)); }
} OUT;

class DebugPrint {
public:
  template <typename T>
  DebugPrint& operator <<(const T& v) {
#ifdef LOCAL
    cerr << v;
#endif
    return *this;
  }
} debugos;

template <typename OutStream, typename T, typename U>
OutStream& operator<<(OutStream& out, const pair<T, U>& var) {
  return out << var.first << " " << var.second;
}
template <typename OutStream, typename Tuple, size_t I, size_t N,
          enable_if_t<I == N>* = nullptr>
OutStream& tuple_impl(OutStream& out, const Tuple& var) {
  return out;
}
template <typename OutStream, typename Tuple, size_t I, size_t N,
          enable_if_t<I != N>* = nullptr>
OutStream& tuple_impl(OutStream& out, const Tuple& var) {
  out << get<I>(var) << " ";
  return tuple_impl<OutStream, Tuple, I+1, N>(out, var);
}
template <typename OutStream, typename... Ts>
OutStream& operator<<(OutStream& out, const tuple<Ts...>& var) {
  return tuple_impl<OutStream, tuple<Ts...>, 0, sizeof...(Ts)>(out, var);
}
template <typename InStream, typename T, typename U>
InStream& operator>>(InStream& in, pair<T, U>& var) {
  return in >> var.first >> var.second;
}
template <typename InStream, typename Tuple, size_t I, size_t N,
          enable_if_t<I == N>* = nullptr>
InStream& tuple_impl(InStream& in, Tuple& var) {
  return in;
}
template <typename InStream, typename Tuple, size_t I, size_t N,
          enable_if_t<I != N>* = nullptr>
InStream& tuple_impl(InStream& in, Tuple& var) {
  in >> get<I>(var);
  return tuple_impl<InStream, Tuple, I+1, N>(in, var);
}
template <typename InStream, typename... Ts>
InStream& operator>>(InStream& in, tuple<Ts...>& var) {
  return tuple_impl<InStream, tuple<Ts...>, 0, sizeof...(Ts)>(in, var);
}

#pragma GCC diagnostic ignored "-Wshadow"

template <typename T, typename U, typename Merge, typename EMerge, typename Upd>
struct lazy_segtree {
private:
  const int n, h;
  const T unit;
  const U eunit;
  const function<T(T,T)> merge;
  const function<U(U,U)> emerge;
  const function<T(T,U, int)> upd;
  vector<T> data;
  vector<U> lazy;

public:
  // eunit need not be a unit
  lazy_segtree(int n_ = 0, T unit = T(), U eunit = U(), Merge merge = Merge(),
               EMerge emerge = EMerge(), Upd upd = Upd())
      : n(n_), h(32 - __builtin_clz(n_)), unit(unit), eunit(eunit),
        merge(merge), emerge(emerge), upd(upd),
        data(n_ << 1, unit), lazy(n_, eunit) {
    build(0, n);
  }

  // eunit need not be a unit
  template <typename Iter>
  lazy_segtree(Iter first, Iter last, int n_, T unit = T(), U eunit = U(),
               Merge merge = Merge(), EMerge emerge = EMerge(), Upd upd = Upd())
      : n(n_), h(32 - __builtin_clz(n_)), unit(unit), eunit(eunit),
        merge(merge), emerge(emerge), upd(upd),
        data(n_ << 1, unit), lazy(n_, eunit) {
    assign(first, last);
  }

private:
  void apply(int p, U e, int sz) {
    if (e == eunit) return;
    data[p] = upd(data[p], e, sz);
    if (p < n) {
      if (lazy[p] == eunit) lazy[p] = e;
      else lazy[p] = emerge(lazy[p], e);
    }
  }

  void pushdown(int p, int sz) {
    if (p >= n or lazy[p] == eunit) return;
    apply(p << 1, lazy[p], sz >> 1);
    apply(p << 1 | 1, lazy[p], sz >> 1);
    lazy[p] = eunit;
  }

  void pushup(int p, int sz) {
    if (p >= n) return;
    data[p] = merge(data[p << 1], data[p << 1 | 1]);
    if (lazy[p] != eunit) data[p] = upd(data[p], lazy[p], sz);
  }

  void flush(int l, int r) {
    int s = h, k = 1 << h;
    for (l += n, r += n - 1; s > 0; s--, k >>= 1)
      for (int p = l >> s; p <= r >> s; p++)
        pushdown(p, k);
  }

  void build(int l, int r) {
    int sz = 2;
    for (l += n, r += n - 1; l > 1; sz <<= 1) {
      l >>= 1, r >>= 1;
      for (int p = l; p <= r; p++) pushup(p, sz);
    }
  }

  template <typename Iter>
  void assign(Iter first, Iter last) {
    copy(first, last, data.begin() + n);
    build(0, n);
  }

public:
  void modify(int l, int r, U e) {
    if (e == eunit) return;
    flush(l, l + 1);
    flush(r - 1, r);
    int l0 = l, r0 = r, k = 1;
    for (l += n, r += n; l < r; l >>= 1, r >>= 1, k <<= 1) {
      if (l & 1) apply(l++, e, k);
      if (r & 1) apply(--r, e, k);
    }
    build(l0, l0 + 1);
    build(r0 - 1, r0);
  }

  T query(int l, int r) {
    flush(l, l + 1);
    flush(r - 1, r);
    T resl = unit, resr = unit;
    for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
      if (l & 1) resl = merge(resl, data[l++]);
      if (r & 1) resr = merge(data[--r], resr);
    }
    return merge(resl, resr);
  }
};
#pragma GCC diagnostic warning "-Wshadow"

template <typename T>
struct minT {
  T operator()(T a, T b) const { return min(a, b); }
};

template <typename T>
struct maxT {
  T operator()(T a, T b) const { return max(a, b); }
};

template <typename T>
struct assign {
  T operator()(T a, T b, int k = 0) const { return b; }
};

template <typename T>
struct plusT {
  T operator()(T a, T b, int k) const {
    return a + b * k;
  }
};


int main() {
  int n = IN, q = IN;
  lazy_segtree<int, int, minT<int>, assign<int>, assign<int>>
    st(n, (1u << 31) - 1, (1u << 31) - 1);
  rep(q) {
    ll c = IN;
    if (c == 0) {
      ll s = IN, t = IN, x = IN;
      st.modify(s, t+1, x);
    } else {
      ll s = IN, t = IN;
      OUT(st.query(s, t+1));
    }
  }
}


Measured memory_bytes: 4032