#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <math.h>
#include <complex>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <unordered_map>
#include <set>
#include <bitset>
#include <functional>
#include <assert.h>
using ll=long long;
#define int ll
#define rng(i,a,b) for(int i=int(a);i<int(b);i++)
#define rep(i,b) rng(i,0,b)
#define gnr(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define per(i,b) gnr(i,0,b)
#define eb emplace_back
#define all(x) x.begin(),x.end()
#define SZ(x) x.size()
#define fi first
#define se second
const int INF = (1ll<<31)-1;
using namespace std;

template<class T> using vc=vector<T>;
template<class T> using vvc=vc<vc<T>>;

using pi=pair<int,int>;
using vi=vc<int>;

template<class T>
inline bool chmax(T &a,T b){if(a<b){a=b;return true;}return false;}
template<class T>
inline bool chmin(T &a,T b){if(a>b){a=b;return true;}return false;}

//https://github.com/beet-aizu/library/blob/master/segtree/basic/chien.cpp
template <typename T,typename E>
struct SegmentTree{
    using F = function<T(T,T)>;
    using G = function<T(T,E)>;
    using H = function<E(E,E)>;
    int n,height;
    F f;
    G g;
    H h;
    T ti;
    E ei;
    vector<T> dat;
    vector<E> laz;
    SegmentTree(F f,G g,H h,T ti,E ei):
        f(f),g(g),h(h),ti(ti),ei(ei){}

    void init(int n_){
        n=1;height=0;
        while(n<n_) n<<=1,height++;
        dat.assign(2*n,ti);
        laz.assign(2*n,ei);
    }
    void build(const vector<T> &v){
        int n_=v.size();
        init(n_);
        for(int i=0;i<n_;i++) dat[n+i]=v[i];
        for(int i=n-1;i;i--)
            dat[i]=f(dat[(i<<1)|0],dat[(i<<1)|1]);
    }
    inline T reflect(int k){
        return laz[k]==ei?dat[k]:g(dat[k],laz[k]);
    }
    inline void propagate(int k){
        if(laz[k]==ei) return;
        laz[(k<<1)|0]=h(laz[(k<<1)|0],laz[k]);
        laz[(k<<1)|1]=h(laz[(k<<1)|1],laz[k]);
        dat[k]=reflect(k);
        laz[k]=ei;
    }
    inline void thrust(int k){
        for(int i=height;i;i--) propagate(k>>i);
    }
    inline void recalc(int k){
        while(k>>=1)
            dat[k]=f(reflect((k<<1)|0),reflect((k<<1)|1));
    }
    void update(int a,int b,E x){
        if(a>=b) return;
        thrust(a+=n);
        thrust(b+=n-1);
        for(int l=a,r=b+1;l<r;l>>=1,r>>=1){
            if(l&1) laz[l]=h(laz[l],x),l++;
            if(r&1) --r,laz[r]=h(laz[r],x);
        }
        recalc(a);
        recalc(b);
    }
    void set_val(int a,T x){
        thrust(a+=n);
        dat[a]=x;laz[a]=ei;
        recalc(a);
    }
    T query(int a,int b){
        if(a>=b) return ti;
        thrust(a+=n);
        thrust(b+=n-1);
        T vl=ti,vr=ti;
        for(int l=a,r=b+1;l<r;l>>=1,r>>=1) {
            if(l&1) vl=f(vl,reflect(l++));
            if(r&1) vr=f(reflect(--r),vr);
        }
        return f(vl,vr);
    }

    template<typename C>
    int find(int st,C &check,T &acc,int k,int l,int r){
        if(l+1==r){
            acc=f(acc,reflect(k));
            return check(acc)?k-n:-1;
    }
        propagate(k);
        int m=(l+r)>>1;
        if(m<=st) return find(st,check,acc,(k<<1)|1,m,r);
        if(st<=l&&!check(f(acc,dat[k]))){
            acc=f(acc,dat[k]);
            return -1;
        }
        int vl=find(st,check,acc,(k<<1)|0,l,m);
        if(~vl) return vl;
        return find(st,check,acc,(k<<1)|1,m,r);
    }
    template<typename C>
    int find(int st,C &check){
        T acc=ti;
        return find(st,check,acc,1,0,n);
    }
};

signed main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout<<fixed<<setprecision(20);

    auto f=[](int a,int b){return min(a,b);};
    auto g=[](int a,pi b){return b.se;};
    auto h=[](pi a,pi b){return max(a,b);};
    SegmentTree<int,pi> seg(f,g,h,INF,pi(-1,INF));
    int n,q; cin >> n >> q;
    seg.init(n);
    rep(i,q){
        int s; cin >> s;
        if(s==0){
            int t,u,v; cin >> t >> u >> v;
            seg.update(t,u+1,pi(i,v));
        }
        else {
            int t,u; cin >> t >> u;
            cout << seg.query(t,u+1) << "\n";
        }
    }
}


Measured memory_bytes: 8876