#pragma GCC optimize ("O3")
#include "bits/stdc++.h"

using namespace std;
using ll = long long int;

#define debugos clog
#define debug(v) {printf("L%d %s > ",__LINE__,#v);debugos<<(v)<<endl;}
#define debugv(v) {printf("L%d %s > ",__LINE__,#v);for(auto e:(v)){debugos<<e<<" ";}debugos<<endl;}
#define debuga(m,w) {printf("L%d %s > ",__LINE__,#m);for(int x=0;x<(w);x++){debugos<<(m)[x]<<" ";}debugos<<endl;}
#define debugaa(m,h,w) {printf("L%d %s >\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){debugos<<(m)[y][x]<<" ";}debugos<<endl;}}
#define ALL(v) (v).begin(),(v).end()
#define repeat(cnt,l) for(remove_reference<remove_const<decltype(l)>::type>::type cnt=0;(cnt)<(l);++(cnt))
#define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt))
#define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt))
#define diterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);--(cnt))
const ll MD = 1000000007ll; const long double PI = 3.1415926535897932384626433832795L;
inline void assert_call(bool assertion, function<void()> f) { if (!assertion) { cerr << "assertion fault:" << endl; f(); abort(); } }
template<typename T1, typename T2> inline ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << '(' << p.first << ':' << p.second << ')'; return o; }
template<typename Vec> inline ostream& _ostream_vecprint(ostream& os, const Vec& a) {
    os << '['; for (const auto& e : a) os << ' ' << e << ' '; os << ']'; return os;
}
template<typename T> inline ostream& operator<<(ostream& o, const vector<T>& v) { return _ostream_vecprint(o, v); }
template<typename T, size_t S> inline ostream& operator<<(ostream& o, const array<T, S>& v) { return _ostream_vecprint(o, v); }
template<typename T> inline T& maxset(T& to, const T& val) { return to = max(to, val); }
template<typename T> inline T& minset(T& to, const T& val) { return to = min(to, val); }
void bye(string s, int code = 0) { cout << s << endl; exit(code); }
mt19937_64 randdev(8901016);
template<typename T> inline T rand(T l, T h) { return uniform_int_distribution<T>(l, h)(randdev); }
template<> inline double rand<double>(double l, double h) { return uniform_real_distribution<double>(l, h)(randdev); }
template<> inline float rand<float>(float l, float h) { return uniform_real_distribution<float>(l, h)(randdev); }


#if defined(_WIN32) || defined(_WIN64)
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#elif defined(__GNUC__)
#else
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
namespace {
#define isvisiblechar(c) (0x21<=(c)&&(c)<=0x7E)
    class MaiScanner {
    public:
        template<typename T> void input_integer(T& var) noexcept {
            var = 0; T sign = 1;
            int cc = getchar_unlocked();
            for (; cc < '0' || '9' < cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc && cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var * sign;
        }
        inline int c() noexcept { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) noexcept { input_integer<int>(var); return *this; }
        inline MaiScanner& operator>>(long long& var) noexcept { input_integer<long long>(var); return *this; }
        inline MaiScanner& operator>>(string& var) {
            int cc = getchar_unlocked();
            for (; !isvisiblechar(cc); cc = getchar_unlocked());
            for (; isvisiblechar(cc); cc = getchar_unlocked())
                var.push_back(cc);
            return *this;
        }
        template<typename IT> void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; }
    };
    class MaiPrinter {
    public:
        template<typename T>
        void output_integer(T var) noexcept {
            if (var == 0) { putchar_unlocked('0'); return; }
            if (var < 0)
                putchar_unlocked('-'),
                var = -var;
            char stack[32]; int stack_p = 0;
            while (var)
                stack[stack_p++] = '0' + (var % 10),
                var /= 10;
            while (stack_p)
                putchar_unlocked(stack[--stack_p]);
        }
        inline MaiPrinter& operator<<(char c) noexcept { putchar_unlocked(c); return *this; }
        inline MaiPrinter& operator<<(int var) noexcept { output_integer<int>(var); return *this; }
        inline MaiPrinter& operator<<(long long var) noexcept { output_integer<long long>(var); return *this; }
        inline MaiPrinter& operator<<(char* str_p) noexcept { while (*str_p) putchar_unlocked(*(str_p++)); return *this; }
        inline MaiPrinter& operator<<(const string& str) {
            const char* p = str.c_str();
            const char* l = p + str.size();
            while (p < l) putchar_unlocked(*p++);
            return *this;
        }
        template<typename IT> void join(IT begin, IT end, char sep = ' ') { for (bool b = 0; begin != end; ++begin, b = 1) b ? *this << sep << *begin : *this << *begin; }
    };
}
MaiScanner scanner;
MaiPrinter printer;


template<typename T>
//using T = ll;
class SegmentTree {
public:
    struct IdxVal {
        int index;
        T value;
        inline IdxVal(int _i = 0, const T& _v = T()) :index(_i), value(_v) { }
        inline void set(int i, const T& v) { index = i; value = v; }
        inline bool operator<(const T& t) const { return value < t; }
        inline bool operator==(const T& t) const { return value == t; }
        inline bool operator<(const IdxVal& iv) const { return value < iv.value || (value == iv.value && index < iv.index); }
        inline bool operator==(const IdxVal& iv) const { return index == iv.index && value == iv.value; }
    };

    enum struct Cmd{
        None, Add, Flat
    };

    struct Node {
        T sum, lazyValue;
        IdxVal max;
        Cmd lazyType;
    };

private:
    const int size_;
    vector<T> leaf_data_;
    vector<Node> node_data_;
    T* leaf_;
    Node* node_;

    void _resize() {
        leaf_data_.resize(size_);
        node_data_.resize(size_ - 1);

        leaf_ = &leaf_data_[0];
        node_ = &node_data_[0] - 1;
    }

    void _init() {
        for (int i = size_ - 1; 0 < i; --i) {
            int c = i << 1;
            if (size_ <= c)
                node_[i].max.set(c - size_, leaf_[c - size_]);
            else
                node_[i].max = node_[c].max;
            node_[i].lazyType = Cmd::None;
            node_[i].sum = node_[i].lazyValue = 0;
        }
    }
public:

    inline void fill(T val) {
        std::fill(leaf_data_.begin(), leaf_data_.end(), val);
        _init();
    }

    SegmentTree(int _n) :
        size_([](int _n) {int s = 8; while (s < _n) s <<= 1; return s; }(_n))
    {
        _resize();
        _init();
    }
    SegmentTree(int _n, const T& _fillVal) :
        size_([](int _n) {int s = 8; while (s < _n) s <<= 1; return s; }(_n))
    {
        _resize();
        fill(_fillVal);
    }


private:
    // lazyを適応する(子を呼ぶ前に呼ぶ)
    // width: ptrが担当するnodeの範囲の大きさ(ptr = 1 ならば size_)
    inline void _applyDown(int ptr, int width) {
        width >>= 1;
        //if (size_ <= ptr) return;
        if (node_[ptr].lazyType == Cmd::Add) {
            int c = ptr << 1;

            if (size_ <= c) {
                leaf_[c - size_] += node_[ptr].lazyValue;
                leaf_[c + 1 - size_] += node_[ptr].lazyValue;
            }
            else {
                node_[c].sum += node_[ptr].lazyValue * width;
                node_[c].max.value += node_[ptr].lazyValue;
                node_[c].lazyValue += node_[ptr].lazyValue;
                if (node_[c].lazyType == Cmd::None)
                    node_[c].lazyType = Cmd::Add;

                node_[c + 1].sum += node_[ptr].lazyValue * width;
                node_[c + 1].max.value += node_[ptr].lazyValue;
                node_[c + 1].lazyValue += node_[ptr].lazyValue;
                if (node_[c + 1].lazyType == Cmd::None)
                    node_[c + 1].lazyType = Cmd::Add;
            }

            node_[ptr].lazyType = Cmd::None;
            node_[ptr].lazyValue = 0;
        }
        else if (node_[ptr].lazyType == Cmd::Flat) {
            node_[ptr].lazyType = Cmd::None;
            int c = ptr << 1;

            if (size_ <= c) {
                leaf_[c - size_] = node_[ptr].lazyValue;
                leaf_[c + 1 - size_] = node_[ptr].lazyValue;
            }
            else {
                node_[c].sum = node_[ptr].lazyValue * width;
                node_[c].max.value = node_[ptr].lazyValue;
                node_[c].lazyValue = node_[ptr].lazyValue;
                node_[c].lazyType = Cmd::Flat;

                node_[c + 1].sum = node_[ptr].lazyValue * width;
                node_[c + 1].max.value = node_[ptr].lazyValue;
                node_[c + 1].lazyValue = node_[ptr].lazyValue;
                node_[c + 1].lazyType = Cmd::Flat;
            }

            node_[ptr].lazyType = Cmd::None;
            node_[ptr].lazyValue = 0;
        }
    }

    // lazyを適応する(子を呼んだ後に呼ぶ)
    inline void _applyUp(int ptr) {
        if (size_ <= ptr << 1) {
            int i = (ptr << 1) - size_;
            if (leaf_[i] < leaf_[i + 1])
                node_[ptr].max.set(i + 1, leaf_[i + 1]);
            else
                node_[ptr].max.set(i, leaf_[i]);
            node_[ptr].sum = leaf_[i] + leaf_[i + 1];
        }
        else {
            if (node_[(ptr << 1)].max.value < node_[(ptr << 1) + 1].max.value)
                node_[ptr].max = node_[(ptr << 1) + 1].max;
            else
                node_[ptr].max = node_[(ptr << 1)].max;
            node_[ptr].sum = node_[ptr << 1].sum + node_[(ptr << 1) + 1].sum;
        }
    }

    // _downward_applyDown(ptr1): leaf[ptr1]の値を正しくする．
    void _downward_applyDown(int ptr1, int width = 1) {
        if (1 < ptr1) _downward_applyDown(ptr1 >> 1, width << 1);
        _applyDown(ptr1, width);
    }


    void _setValueRange(int begin, int end, T val, int ptr, int rangebegin, int rangeend) {

        if (rangeend <= begin || end <= rangebegin) return; // note:範囲外
        if (begin <= rangebegin && rangeend <= end) {
            if (size_ <= ptr) {
                leaf_[rangebegin] = val;
            }
            else {
                node_[ptr].sum = val * (rangeend - rangebegin);
                node_[ptr].max.value = val;
                node_[ptr].lazyType = Cmd::Flat;
                node_[ptr].lazyValue = val;
            }
            return;
        }

        _applyDown(ptr, rangeend - rangebegin);

        _setValueRange(begin, end, val, ptr << 1, rangebegin, (rangebegin + rangeend) >> 1);
        _setValueRange(begin, end, val, (ptr << 1) + 1, (rangebegin + rangeend) >> 1, rangeend);

        _applyUp(ptr);
    }

    void _addValueRange(int begin, int end, T val, int ptr, int rangebegin, int rangeend) {

        if (rangeend <= begin || end <= rangebegin) return; // note:範囲外
        if (begin <= rangebegin && rangeend <= end) {
            if (size_ <= ptr) {
                leaf_[rangebegin] += val;
            }
            else {
                node_[ptr].sum += val * (rangeend - rangebegin);
                node_[ptr].max.value += val;
                node_[ptr].lazyValue += val;
                if (node_[ptr].lazyType == Cmd::None)
                    node_[ptr].lazyType = Cmd::Add;
            }
            return;
        }

        _applyDown(ptr, rangeend - rangebegin);

        _addValueRange(begin, end, val, ptr << 1, rangebegin, (rangebegin + rangeend) >> 1);
        _addValueRange(begin, end, val, (ptr << 1) + 1, (rangebegin + rangeend) >> 1, rangeend);

        _applyUp(ptr);
    }

    T _getSumRange(int begin, int end, int ptr, int rangebegin, int rangeend) {
        if (rangeend <= begin || end <= rangebegin) return 0; // note:範囲外
        if (begin <= rangebegin && rangeend <= end) {
            if (size_ <= ptr)
                return leaf_[rangebegin];
            else
                return node_[ptr].sum;
        }

        _applyDown(ptr, rangeend - rangebegin);

        return _getSumRange(begin, end, ptr << 1, rangebegin, (rangebegin + rangeend) >> 1)
            + _getSumRange(begin, end, (ptr << 1) + 1, (rangebegin + rangeend) >> 1, rangeend);
    }

    IdxVal _getMaxRange(int begin, int end, int ptr, int rangebegin, int rangeend) {
        if (rangeend <= begin || end <= rangebegin) return IdxVal(-1); // note:範囲外
        if (begin <= rangebegin && rangeend <= end) {
            if (size_ <= ptr)
                return IdxVal(rangebegin, leaf_[rangebegin]);
            else
                return node_[ptr].max;
        }

        _applyDown(ptr, rangeend - rangebegin);

        auto l = _getMaxRange(begin, end, ptr << 1, rangebegin, (rangebegin + rangeend) >> 1);
        auto r = _getMaxRange(begin, end, (ptr << 1) + 1, (rangebegin + rangeend) >> 1, rangeend);

        if (l.index == -1) return move(r);
        if (r.index == -1) return move(l);
        return l.value < r.value ? move(r) : move(l);
    }

public:
    // [index] の値を求める
    inline T getValue(int index) {
        _downward_applyDown((index + size_) >> 1);
        return leaf_[index];
    }

    // [index] の値を書き換える
    inline T setValue(int index, T val) {
        _downward_applyDown((index + size_) >> 1);
        T diff = val - leaf_[index];
        leaf_[index] = val;

        for (int ptr = (index + size_); 1 < ptr;) {
            ptr >>= 1;
            node_[ptr].sum -= diff;
            _applyUp(ptr);
        }
    }

    // [index] の値に加算する
    inline T addValue(int index, T val) {
        _downward_applyDown((index + size_) >> 1);
        leaf_[index] += val;

        for (int ptr = (index + size_); 1 < ptr;) {
            ptr >>= 1;
            node_[ptr].sum += val;
            _applyUp(ptr);
        }
    }

    // 区間[begin,end)全てにvalをセットする
    inline void setValueRange(int begin, int end, T val) {
        _setValueRange(begin, end, val, 1, 0, size_);
    }

    // 区間[begin,end)に一様にvalを加算する
    inline void addValueRange(int begin, int end, T val) {
        _addValueRange(begin, end, val, 1, 0, size_);
    }

    // 区間[begin,end)の和を求める
    inline T getSumRange(int begin, int end) {
        return _getSumRange(begin, end, 1, 0, size_);
    }

    // 区間[begin,end)の最大値とその位置を求める
    inline IdxVal getMaxRange(int begin, int end) {
        return _getMaxRange(begin, end, 1, 0, size_);
    }
};


int main_dsl_2_A() {
    int N, Q;
    scanner >> N >> Q;

    SegmentTree<ll> segtree(N, -2147483647);
    repeat(_, Q) {
        int c, x, y;
        scanner >> c >> x >> y;
        if (c == 0) {
            segtree.setValue(x, -y);
        }
        else if (c == 1) {
            auto a = segtree.getMaxRange(x, y + 1);
            printer << -a.value << '\n';
        }
    }
    return 0;
}
int main_dsl_2_B() {
    int N, Q;
    scanner >> N >> Q;

    SegmentTree<ll> segtree(N, 0);
    repeat(_, Q) {
        int c, x, y;
        scanner >> c >> x >> y;
        if (c == 0) {
            segtree.addValue(x - 1, y);
        }
        else if (c == 1) {
            auto a = segtree.getSumRange(x - 1, y);
            printer << a << '\n';
        }
    }
    return 0;
}
int main_dsl_2_D() {
    int N, Q;
    scanner >> N >> Q;
    SegmentTree<ll> segtree(N, 2147483647);

    repeat(_, Q) {
        int c, s, t, x;
        scanner >> c;
        if (c == 0) {
            scanner >> s >> t >> x;
            segtree.setValueRange(s, t + 1, x);
        }
        else if (c == 1) {
            scanner >> s;
            auto a = segtree.getValue(s);
            printer << a << '\n';
        }
    }
    return 0;
}
int main_dsl_2_E() {
    int N, Q;
    scanner >> N >> Q;

    SegmentTree<ll> segtree(N);
    repeat(_, Q) {
        int c, s, t, x;
        scanner >> c;
        if (c == 0) {
            scanner >> s >> t >> x;
            segtree.addValueRange(s, t + 1, x);
        }
        else if (c == 1) {
            scanner >> s;
            auto e = segtree.getValue(s);
            printer << e << '\n';
        }
    }
    return 0;
}
int main_dsl_2_F() {
    int N, Q;
    scanner >> N >> Q;
    SegmentTree<ll> segtree(N, -2147483647);

    repeat(_, Q) {
        int c, s, t, x;
        scanner >> c;
        if (c == 0) {
            scanner >> s >> t >> x;
            segtree.setValueRange(s, t + 1, -x);
        }
        else if (c == 1) {
            scanner >> s >> t;
            auto a = segtree.getMaxRange(s, t + 1);
            printer << -a.value << '\n';
        }
    }
    return 0;
}
int main_dsl_2_G() {
    int m, n;
    int q;
    scanner >> n >> q;

    SegmentTree<ll> seg(n);

    repeat(_, q) {
        int t;
        scanner >> t;
        if (t == 0) {
            int s, t, x;
            scanner >> s >> t >> x;
            --s; --t;
            seg.addValueRange(s, t + 1, x);
        }
        else {
            int s, t;
            scanner >> s >> t;
            --s; --t;
            printer << (seg.getSumRange(s, t + 1)) << '\n';
        }
    }
    return 0;
}

int main_dsl_2_H() {
    int N, Q;
    scanner >> N >> Q;

    SegmentTree<ll> segtree(N);
    repeat(_, Q) {
        int q, s, t, x;
        scanner >> q;
        if (q == 0) {
            scanner >> s >> t >> x;
            segtree.addValueRange(s, t + 1, -x);
        }
        else if (q == 1) {
            scanner >> s >> t;
            auto a = segtree.getMaxRange(s, t + 1);
            printer << a.value << '\n';
        }
    }
    return 0;
}
int main_dsl_2_I() {
    int N, Q;
    scanner >> N >> Q;
    SegmentTree<ll> segtree(N);

    repeat(_, Q) {
        int c, s, t, x;
        scanner >> c;
        if (c == 0) {
            scanner >> s >> t >> x;
            segtree.setValueRange(s, t + 1, x);
        }
        else if (c == 1) {
            scanner >> s >> t;
            auto a = segtree.getSumRange(s, t + 1);
            printer << a << '\n';
        }
    }
    return 0;
}

int main() {
    // main_dsl_2_A();
    // main_dsl_2_B();
    // main_dsl_2_D();
    // main_dsl_2_E();
    main_dsl_2_F();
    // main_dsl_2_G();
    // main_dsl_2_H();
    // main_dsl_2_I();
    return 0;
}



Measured memory_bytes: 8888