#include<iostream>
#include<cassert>
#define GET_MACRO(_1,_2,_3,_4,_5,_6,_7,_8,NAME,...) NAME
#define pr(...) cerr<< GET_MACRO(__VA_ARGS__,pr8,pr7,pr6,pr5,pr4,pr3,pr2,pr1)(__VA_ARGS__) <<endl
#define pr1(a) (#a)<<"="<<(a)<<" "
#define pr2(a,b) pr1(a)<<pr1(b)
#define pr3(a,b,c) pr1(a)<<pr2(b,c)
#define pr4(a,b,c,d) pr1(a)<<pr3(b,c,d)
#define pr5(a,b,c,d,e) pr1(a)<<pr4(b,c,d,e)
#define pr6(a,b,c,d,e,f) pr1(a)<<pr5(b,c,d,e,f)
#define pr7(a,b,c,d,e,f,g) pr1(a)<<pr6(b,c,d,e,f,g)
#define pr8(a,b,c,d,e,f,g,h) pr1(a)<<pr7(b,c,d,e,f,g,h)
#define prArr(a) {cerr<<(#a)<<"={";int i=0;for(auto t:(a))cerr<<(i++?", ":"")<<t;cerr<<"}"<<endl;}
template<typename T>
class Deque{
public:
  T *val;
  int sz;
  int length;
  int head, tail;
  
  Deque(){sz = 0, length = 0, val = new T[0];}
  Deque(int size, T init = T()){
    length = 1;
    while(length < size) length *= 2;
    val = new T[length];
    sz = size;
    head = 0;
    tail = 0;
    for(int i=0;i<size;i++) val[tail++] = init;
  }
  
  Deque(const Deque &t){
    sz = t.size();
    length = 1;
    while(length < sz) length *= 2;
    val = new T[length];
    head = 0;
    tail = 0;
    for(int i=0;i<sz;i++) val[tail++] = t[i];
  }

  ~Deque(){
    delete [] val;
  }
  
  T& operator [] (int i){assert(0 <= i && i < sz);return val[(head + i)%length];}
  T& operator [] (int i)const{assert(0 <= i && i < sz);return val[(head + i)%length];}
  int size()const{return sz;}
  int empty()const{return sz == 0;}
  void resize(int n, T v=T()){
    while(n < size()) pop_back();
    while(n > size()) push_back(v);
  }
  
  void increaseMemory(){
    int length_ = length;
    
    length = length * 2;
    if(length == 0) length = 1;
    T *val2 = new T[length];
    for(int i=0;i<sz;i++) val2[i] = val[(head + i)%length_];
    head = 0;
    tail = sz;
    delete [] val;
    val = val2;
  };
  
  void push_back(T v){
    if(sz == length) increaseMemory();
    sz++;
    val[tail++] = v;
    if(tail == length) tail = 0;
  }
  
  void push_front(int v){
    if(sz == length) increaseMemory();
    sz++;
    head--;
    if(head == -1) head = length - 1;
    val[head] = v;
  }

  void pop_back(){
    assert(sz > 0);
    sz--;
    tail--;
    if(tail == -1) tail = length - 1;
  }
  
  void pop_front(){
    assert(sz > 0);
    sz--;
    head++;
    if(head == length) head = 0;
  }
};
template <typename T>
using vector = Deque<T>;


template<class T>T max(T a, T b){return a >= b? a:b;}
template<class T>T min(T a, T b){return a <= b? a:b;}
template<typename dtype, dtype initValue /*範囲外の時に返す値*/>
class RMQ{
public : 
  
  struct data{
    bool type; //0 - empty   , 1 - update
    dtype value;
  };
  
  int n,n_;
  vector<dtype> dat;
  vector<data> td;
  int toMax;          //0 -> RangeMin 1->RangeMax;
  
  RMQ(){n=-1;}
  RMQ(int n_, int toMax = 0):n_(n_),toMax(toMax){
    n=1;
    while(n<n_)n*=2;
    td.resize(2*n-1,(data){0,initValue});
    dat.resize(2*n-1,initValue);
  }

  inline dtype merge(dtype a, dtype b){return toMax? max(a, b):min(a, b);}
  
  
  dtype dfs(int a,int b,dtype x,bool flag,int k,int l,int r){
    if(r <= a || b <= l) return flag? dat[k]:initValue;
    if(a <= l && r <= b){
      if(flag == true){
        td[k]=(data){1,x};
        dat[k]=x;
      }
      return dat[k];
    }
    
    if(td[k].type){
      td[k].type = 0;
      dat[k*2+1] = dat[k*2+2] = td[k].value;
      td[k*2+1] = td[k*2+2] = (data){1,td[k].value};
    }

    dtype vl=dfs(a, b, x, flag, k*2+1, l, (l+r)/2);
    dtype vr=dfs(a, b, x, flag, k*2+2, (l+r)/2, r);
    return flag? (dat[k] = merge(vl, vr)):merge(vl,vr);
  }
  
  //[l,r)の値をxに変更　update(l,r,x)
  void update(int l,int r,dtype x){
    assert(l <= r), assert(l <= n && r <= n), assert(l >= 0 && r >= 0);
    dfs(l, r, x, true, 0, 0, n);
  }
  
  //[l,r)の最小値を得る　find(l,r);
  dtype get(int l,int r){
    assert(l <= r), assert(l <= n && r <= n), assert(l >= 0 && r >= 0);
    return dfs(l, r, initValue , false, 0 , 0 ,n);
  }
};

int main(){
  int q,n;
  std::cin>>n>>q;
  typedef long long ll;
  RMQ <ll, (1LL<<31)-1> T(n, 0);

  while(q--){
    int cmd,s,t,x;
    scanf("%d%d%d",&cmd,&s,&t);
    if(cmd==0)std::cin>>x,T.update(s,t+1,x);
    else std::cout <<T.get(s,t+1)<<std::endl;
  }
  return 0;



}



Measured memory_bytes: 10916