//#define debug //*******************************************************************************************************************************************

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// [Tips]
// XCode??§???EOF??\??????Ctrl+D
// ?\???Alt+\
// ans???????§?INT?????????2,147,483,647????¶????????????¨??????????????§long long?????£???????????????????????????
// 2?????°??¨??? = dout << static_cast<bitset<8> >(x)
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////




////////////////////////////////////////
//AIZU
//Range Update Query (RUQ)
//
//Segment Tree??§????£?
////////////////////////////////////////


#ifdef debug
#include <chrono>
#endif

#include <iostream>
#include <algorithm> // next_permutation
#include <iomanip>
#include <cmath>
#include <vector>
#include <sstream>
#include <string>
#include <cstring> //memcpy
#include <cstdio>
#include <stack>
#include <queue>
#include <list>
#include <numeric> //accumulate
#include <map>
//#include <unordered_map> //hash func.
#include <fstream> //ifstream, ofstream
#include <iterator> //insert_iterator::inserter
#include <set>
//#include <random>


//#define NDEBUG //If NDEBUG is defined before #include <cassert>, assert will be ignored. You had better define NDEBUG when u submit the code.
#include <cassert> //assert

using namespace std;


#define dout cout
//If u wanna output to a text file instead of standard output, plz define OUTPUTFILE.
#define OUTPUTFILE "output.txt" //************************************************************
#ifdef OUTPUTFILE
#define dout outputfile
ofstream outputfile(OUTPUTFILE);
#define OutputFilePath "/Users/Nag/Documents/Prgm/Test/DerivedData/Test/Build/Products/Debug/output.txt"
#endif


#define din cin
//If u wanna input from a text file instead of standard input, plz define INPUTFROMTEXTFILE???.
//#define INPUTFILE "input.txt" //**************************************************************
#ifdef INPUTFILE
#define din inputfile
ifstream inputfile(INPUTFILE);
#endif

#define scand(A) scanf("%d", &(A))
#define scans(A) scanf("%s", (A))
#define printd(A) dout << "%d\n", (A))
#define prints(A) dout << "%s\n", (A))
#define disp(A) dout << #A << " = " << setw(3) << (A) << endl
#define disP(A) dout << setw(3) << (A) << " "
#define rep(i,a,n) for(int (i)=(a); (i)<(n); (i)++)
#define show(A,s,g) dout << #A << " = "; rep(__w, (s), (g)) {disP(A[__w]);} dout << endl
#define showi(A,s,g) dout << #A << " = "; rep(__w, (s), (g)) {disP(__w);} dout << endl
#define line  dout << "----------------\n"
#define line2 dout << "================\n"

#define sign(x) ((x)>0)-((x)<0) //x<0: -1, x=0: 0, x>0: +1
#define p(i) ((i)/2)
#define l(i) ((i)*2)
#define r(i) ((i)*2+1)
#define sibling(i) (i^1) //the other sibling of i (ex. 16^1 = 17, 17^1 = 16)
#define isRightChild(i) (i&1) // ex. 16&1 = 0, 17&1 = 1
#define isLeftChild(i) (!(i&1)) // ex. 16&1 = 1, 17&1 = 0


typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef vector<int> vi;
typedef long long ll;
typedef unsigned long long ull;

const int INF = (1LL<<31)-1;
const int NONE = -1;
//const ll INF_LL = (ll)9e18-1LL; //Be careful for overflow.
//const ull INF_ULL = (ull)1e19-1ULL;
//#define MOD 1000000007 //??§???????´???°?????£??¨??¨????????°????????????10???7??????

#define N_MAX 100010 //num of vertex or element
//#define M_MAX 124760 //num of edge
//#define DATA_MAX 1010


int N;
int M; //N????????§??????????°????2????????????????????????upd[M]?????????????????¨??????
int upd[N_MAX<<2]; //Segment Tree. Do not use upd[0]
int mini[N_MAX<<2]; //upd[i]???????????????????°????mini[i]



void init() {
    
    //calc. M
    for(M=1; M<N; M<<=1);
    
    //init upd[]
    rep(i,0,M) {
        upd[i] = NONE;
    }
    rep(i,0,M) {
        upd[M+i] = INF;
    }
    
    //init mini[]
    rep(i,0,M<<1) {
        mini[i] = INF;
    }
    
}



void display() {
#ifdef debug
    dout << "------------------------- display() ---------------------\n";
    
    //    dout << "   "; showi(j,0,N+1);
    //    dout << "C[][] = \n";
    //    rep(i,0,N+1) {
    //        disP(i); dout << " : ";
    //        rep(j,0,N+1) {
    //            disP(C[i][j]);
    //        }
    //        dout << endl;
    //    }
    //    dout << endl;
    
    
    dout << "upd[] = \n";
    dout << "   "; showi(i,0,M);
    
    for(int b=1; b<M<<1; b<<=1) {
        
        int m = M/b;
        
        disP(b); dout << " : ";
        rep(j,0,M) {
            if(j%m==0) disP(upd[b+j/m]==INF ? 999 : upd[b+j/m]);
            else disP("-");
        }
        dout << endl;
        
    }
    dout << endl;
    
    line;
    
    dout << "mini[] = \n";
    dout << "   "; showi(i,0,M);
    
    for(int b=1; b<M<<1; b<<=1) {
        
        int m = M/b;
        
        disP(b); dout << " : ";
        rep(j,0,M) {
            if(j%m==0) disP(mini[b+j/m]==INF ? 999 : mini[b+j/m]);
            else disP("-");
        }
        dout << endl;
        
    }
    dout << endl;
    
    
    dout << "------------------------- end of display() ---------------------\n";
    dout << endl;
    dout << endl;
#endif
}



void lazyPropagation_mini(int i, int x) { //?????????[i] ( ????????????[l,r) ) ???????°???????x?????´??°???????????¨???????????±????????????????????¶?????¬??????
    
#ifdef debug
    dout << "lazyPropagation_mini( i=" << i << ", x=" << x << " )\n";
#endif
    
    
    for( ; i>1 ; i=p(i) ) {
        mini[p(i)] = min( mini[i], mini[sibling(i)] );
    }
    
}



void lazyPropagation_upd(int i, int x) { //upd[i]=x??¨???????????±???1??????????????£????????¬??????
    
#ifdef debug
    dout << "lazyPropagation_upd( i=" << i << ", x=" << x << " )\n";
#endif
    
    
    upd[i] = NONE;
    mini[i] = x;
    
    upd[l(i)] = x;
    mini[l(i)] = x;
    
    upd[r(i)] = x;
    mini[r(i)] = x;
    
    
//    if(i>=M<<1) return;
//    
//    //?????????[i]???????????????????????????x??????????????§?????????????°????????????¶x??¨???????????????mini[i]???????????¶??§x??¨??§??????
//    mini[i] = x;
//
//    if( M<=i and i<M<<1) {
//        upd[i] = x;
//        return;
//    }
//    
//    //?????????????????????????????°????????????
//    upd[i] = NONE;
//    lazyPropagation_upd(l(i), x);
//    lazyPropagation_upd(r(i), x);
    
    
}




void rec_upd(int i, int l, int r, int s, int t, int x) { //????????????[s,t)????????????x??§update??????????????????mini[]??????????????±???????????????????????????????????????????????????[i]??§?????????????????????[l,r)????????°??§??????????????????
    
#ifdef debug
    dout << "--- rec_upd( i=" << i << " ?????????[i]???????????????=[" << l << "," << r << ") | ??´??°????±???????=[" << s << "," << t << "), x=" << x << " )\n";
#endif
    
    //??´??°????±???????[s,t)??¨???????????????????????????[i]???????????????[l,r)??????????????????
    if( r<=s or t<=l ) {
#ifdef debug
        dout << "????????????\n";
#endif
        return;
    }
    
    //??´??°????±???????[s,t)??????????????????????????????[i]???????????????[l,r)????????¨???????????????
    if( s<=l and r<=t ) {
#ifdef debug
        dout << "????????????????????´??°????±???????????????¨?????????????????????\n";
#endif
        upd[i] = x;
        mini[i] = x;
        
#ifdef debug
        dout << "mini[" << i << "] ?????´??°??????????????§??????????????±?????????????????????\n";
#endif
        
        lazyPropagation_mini(i, x);
        
        return;
    }
    
    //???????????§???upd[i]?????´??°???????????£???????????´????????????????????±??????????????????????????????????????°????????????????????§???????????\???
    if( upd[i]!=NONE ) {
#ifdef debug
        dout << "upd[i]????????§?????´??°???????????£??????????????§????????????????????±????????? (1??????????±??????????) ??????????????????\n";
#endif
        lazyPropagation_upd(i, upd[i]);
        display();
    }
    
    //??????????????????????????°????????????
    rec_upd(l(i), l, (l+r)/2, s, t, x);
    
    //??????????????????????????°????????????
    rec_upd(r(i), (l+r)/2, r, s, t, x);
    
}



void ruq(int s, int t, int x) { //?????????[s,t]????????????x?????´??°??????
#ifdef debug
    dout << "--- range update query( s=" << s << ", t=" << t << ", x = " << x << " )\n";
#endif
    
    rec_upd(1, 0, M, s, t+1, x);
    
#ifdef debug
    dout << "=== END OF range update query( s=" << s << ", t=" << t << ", x = " << x << " )\n";
    dout << endl;
    dout << endl;
#endif
}




int rec_mini(int i, int l, int r, int s, int t) { //????????????[s,t)???????°??????????????????????????????°??¢??°?????????????????????????????????[i]??§?????????????????????[l,r)????????°??§??????????????????
    
#ifdef debug
    dout << "--- rec_mini( i=" << i << " ?????????[i]???????????????=[" << l << "," << r << ") | ??¢?´¢????±???????=[" << s << "," << t << ") )\n";
#endif
    
    //??´??°????±???????[s,t)??¨???????????????????????????[i]???????????????[l,r)??????????????????
    if( r<=s or t<=l ) {
#ifdef debug
        dout << "????????????\n";
#endif
        return INF;
    }
    
    //??´??°????±???????[s,t)??????????????????????????????[i]???????????????[l,r)????????¨???????????????
    if( s<=l and r<=t ) {
#ifdef debug
        dout << "????????????????????´??°????±???????????????¨?????????????????????\n";
#endif
        
        return mini[i];
    }
    
    
    //???????????§???upd[i]?????´??°???????????£???????????´????????????????????±??????????????????????????????????????°????????????????????§???????????\???
    if( upd[i]!=NONE ) {
#ifdef debug
        dout << "upd[i]????????§?????´??°???????????£??????????????§????????????????????±???????????????????????????\n";
#endif
        lazyPropagation_upd(i, upd[i]);
        display();
    }


    //????????????
    int mini_l = rec_mini(l(i), l, (l+r)/2, s, t);
    int mini_r = rec_mini(r(i), (l+r)/2, r, s, t);
    
    return min( mini_l, mini_r );
}




int rmq(int s, int t) { //?????????[s,t]???????°?????????????
    
#ifdef debug
    dout << "--- range minimum query( s=" << s << ", t=" << t << " )\n";
#endif
    
    int ret = rec_mini(1, 0, M, s, t+1);
    
#ifdef debug
    disp(ret);
    dout << "=== END OF range minimum query( s=" << s << ", t=" << t << " )\n";
    dout << endl;
    dout << endl;
#endif
    
    return ret;
}









int main() {
    
    //cin, cout????????????  ?????¨??????cin?????????????????¨??¨cin??§???scanf?????????????????¨??¨scanf??§??±?????????????????????
    cin.tie(0); //cin??¨cout??????????????????
    ios::sync_with_stdio(false); //iostream??¨stdio??????????????????
    
    
    //read input data
    din >> N;
    init();
    
    int Q; din >> Q;
    
    
    //------------------------------------------------------------------------------------------
#ifdef debug
    //start timer
    auto startTime = chrono::system_clock::now();
#endif
    //------------------------------------------------------------------------------------------
    
    
    int q, s, t, x;
    rep(i,0,Q) {
        
        display();
        
        din >> q;
        if(q) {
            din >> s >> t;
            cout << rmq(s, t) << endl;
        }
        else {
            din >> s >> t >> x;
            ruq(s, t, x);
        }
    }
    
    
    
    
    
#ifdef debug
    dout << "=== OUTPUT ===\n";
#endif
    
    
    
    
    
    
    
    
    
    
    
    //------------------------------------------------------------------------------------------
#ifdef debug
    //stop timer
    auto endTime = chrono::system_clock::now();
    auto dur = endTime - startTime;
    auto msec = chrono::duration_cast<chrono::milliseconds>(dur).count();
    cout << fixed << setprecision(4) << (double)msec/1000 << " sec \n";
#endif
    //------------------------------------------------------------------------------------------
    
#ifdef INPUTFILE
    inputfile.close();
#endif
    
#ifdef OUTPUTFILE
    outputfile.close();
#ifdef debug
    cout << "\"" << OutputFilePath << "\"" << endl;
#endif
#endif
    
    return 0;
}

Measured memory_bytes: 5268