#include <bits/stdc++.h>
using namespace std;

#define INF_LL (int64)1e18
#define INF (int32)1e9
#define REP(i, n) for(int64 i = 0;i < (n);i++)
#define FOR(i, a, b) for(int64 i = (a);i < (b);i++)
#define all(x) x.begin(),x.end()
#define fs first
#define sc second

using int32 = int_fast32_t;
using uint32 = uint_fast32_t;
using int64 = int_fast64_t;
using uint64 = uint_fast64_t;
using PII = pair<int32, int32>;
using PLL = pair<int64, int64>;

const double eps = 1e-10;

template<typename A, typename B>inline void chmin(A &a, B b){if(a > b) a = b;}
template<typename A, typename B>inline void chmax(A &a, B b){if(a < b) a = b;}

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

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

template<typename T,typename U,typename... V>
typename enable_if<is_same<T, U>::value!=0>::type
fill_v(U &u,const V... v){u=U(v...);}

template<typename T,typename U,typename... V>
typename enable_if<is_same<T, U>::value==0>::type
fill_v(U &u,const V... v){
  for(auto &e:u) fill_v<T>(e,v...);
}

template<class ValueMonoid, template<class...> class Container=::std::vector>
class SegTree{
public:
    using value_structure = ValueMonoid;
    using value_type = typename value_structure::value_type;
    using const_reference = const value_type &;
    using container_type = Container<value_type>;
    using size_type = typename container_type::size_type;

private:
    ::std::vector<value_type> tree;
    size_type size_;

    static size_type getsize(const size_type x){
        size_type ret = 1;
        while(ret < x)
            ret <<= 1;
        return ret;
    }

    inline value_type calc(const value_type a, const value_type b){
        return value_structure::operation(a, b);
    }

    inline void calc_node(const size_type index){
        if(tree.size() <= (index << 1 | 1)) return;
        tree[index] = value_structure::operation(tree[index<<1], tree[index<<1 | 1]);
    }
public:
    SegTree() : size_(0), tree(){}
    SegTree(const size_type size)
            : size_(size), tree(size << 1, value_structure::identity()){}
    template<class InputIterator>
    SegTree(InputIterator first, InputIterator last)
            : size_(::std::distance(first, last)){
        tree = container_type(size_, value_structure::identity());
        tree.insert(tree.end(), first, last);
        for(size_type i = size_;i > 0;i--){
            calc_node(i);
        }
    }

    size_type size() const { return size_; }
    const_reference operator[](const size_type k) const {
        assert(k < size_);
        return tree[k+size_];
    }

    value_type query(size_type l, size_type r){
        assert(l <= r);
        assert(0 <= l && l < size_);
        assert(0 <= r && r <= size_);
        value_type retl = value_structure::identity(), retr = value_structure::identity();
        for(l += size_, r += size_; l < r ; l >>= 1, r >>= 1){
            if(l&1) retl = calc(retl, tree[l++]);
            if(r&1) retr = calc(tree[--r], retr);
        }
        return calc(retl, retr);
    }

    template<class F>
    void update(size_type index, const F& f){
        assert(0 <= index && index < size());
        index += size_;
        tree[index] = f(::std::move(tree[index]));
        while(index >>= 1)
            calc_node(index);
    }

    /*
    template<class F>
    size_type search(const F& f) const { // [0, result) is True and [0, result-1) is not.
        if(f(value_structure::identity()))
            return 0;
        if(!f(tree[1]))
            return size_+1;
        value_type acc = value_structure::identity();
        size_type i = 1;
        while(i <
    }
    */
};

struct value {
    int64 lsum, rsum, sum, maxi;
    value() {}
    value(int64 lsum_, int64 rsum_, int64 sum_, int64 maxi_):
        lsum(lsum_), rsum(rsum_), sum(sum_), maxi(maxi_) {}
};

class v_monoid {
public:
    using value_type = value;
    static value_type identity() { return value(0, 0, 0, -INF_LL); }
    static value_type initializer() { return value(0, 0, 0, 0); }
    static value_type operation(const value_type& l, const value_type& r) {
        value res;
        res.lsum = max(l.lsum, l.sum+r.lsum);
        res.rsum = max(r.rsum, l.rsum+r.sum);
        res.sum = l.sum + r.sum;
        res.maxi = max({l.maxi, r.maxi, l.rsum+r.lsum});
//        cout << "(" << l.lsum << " " << l.rsum << " " << l.sum << " " << l.maxi << ") ";
//        cout << "(" << r.lsum << " " << r.rsum << " " << r.sum << " " << r.maxi << ") ";
//        cout << "(" << res.lsum << " " << res.rsum << " " << res.sum << " " << res.maxi << ") ";
//        cout << endl;
        return res;
    }
};

int main(void){
	cin.tie(0);
	ios::sync_with_stdio(false);
	int64 n, q;
	cin >> n >> q;
	vector<value> a(n);
	REP(i, n) {
	    cin >> a[i].sum;
	    if (a[i].sum > 0) {
	        a[i].lsum = a[i].sum;
	        a[i].rsum = a[i].sum;
	        a[i].maxi = a[i].sum;
	    } else {
            a[i].lsum = 0;
            a[i].rsum = 0;
            a[i].maxi = 0;
	    }
	}
	SegTree<v_monoid> sg(all(a));
	cout << sg.query(0, n).maxi << endl;
	REP(i, q) {
	    int64 k, x;
	    cin >> k >> x; k--;
	    if (x < 0) {
	        sg.update(k, [&](const value& xx) { return value(0, 0, x, 0); });
	    } else {
	        sg.update(k, [&](const value& xx) { return value(x, x, x, x); });
	    }
	    cout << sg.query(0, n).maxi << endl;
	}
}



Measured memory_bytes: 15260