1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
#include "bits/stdc++.h"
using namespace std;

#define rep(i, b, e) for(int i = (b); i <= (e); i++)
#define per(i, b, e) for(int i = (e); i >= (b); i--)
#define FOR(i, b, e) rep(i, b, (e) - 1)
#define SZ(x) int(x.size())
#define all(x) x.begin(), x.end()
#define pb push_back
#define mp make_pair
#define st first
#define nd second
using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;

auto &operator<<(auto &o, pair<auto, auto> p) {
    return o << "(" << p.st << ", " << p.nd << ")"; }
auto operator<<(auto &o, auto x)->decltype(end(x), o) {
    o << "{"; int i=0; for(auto e: x) o << ", " + 2*!i++ << e;
    return o << "}"; }
#ifdef LOCAL
#define deb(x...) cerr << "[" #x "]: ", [](auto...$) { \
    ((cerr << $ << "; "),...) << endl; }(x)
#else
#define deb(...)
#endif

void solve() {
    int n, c;
    cin >> n >> c;
    vector<pii> vec(n);
    for(auto &[a, w]: vec) cin >> a >> w;
    map<int, ll> wynik;
    set<pair<ll, int>> bests;
    FOR(i, 1, 500'001) bests.insert({0, i});
    auto comp = [&c](pair<ll, int> a, pair<ll, int> b) {
        return a.st + b.st - c * (a.nd != b.nd);
    };
    FOR(i, 0, n) {
        int j = i;
        while(j < n && vec[i].st == vec[j].st) j++;
        vector<pair<ll, int>> nowe;
        FOR(k, i, j) {
            auto me = vec[k];
            auto oth1 = *prev(bests.end());
            auto oth2 = mp(wynik[me.nd], me.nd);
            nowe.pb({max(comp(me, oth1), comp(me, oth2)), me.nd});
        }
        for(auto &[sc, kto]: nowe) if(wynik[kto] < sc) {
            bests.erase({wynik[kto], kto});
            wynik[kto] = sc;
            bests.insert({wynik[kto], kto});
        }
        i = j - 1;
    }
    cout << prev(bests.end())->st << '\n';
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int tt = 1;
    // cin >> tt;
    FOR(te, 0, tt) solve();
    return 0;
}