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
67
68
69
70
71
72
73
74
75
76
77
78
79
80
// Arti1990, II UWr

#include <bits/stdc++.h>

#define forr(i, n)                  for(int i=0; i<n; i++)
#define FOREACH(iter, coll)         for(auto iter = coll.begin(); iter != coll.end(); ++iter)
#define FOREACHR(iter, coll)        for(auto iter = coll.rbegin(); iter != coll.rend(); ++iter)
#define lbound(P,K,FUN)             ({auto SSS=P, PPP = P-1, KKK=(K)+1; while(PPP+1!=KKK) {SSS = (PPP+(KKK-PPP)/2); if(FUN(SSS)) KKK = SSS; else PPP = SSS;} PPP;})
#define testy()                     int _tests; cin>>_tests; FOR(_test, 1, _tests)
#define CLEAR(tab)                  memset(tab, 0, sizeof(tab))
#define CONTAIN(el, coll)           (coll.find(el) != coll.end())
#define FOR(i, a, b)                for(int i=a; i<=b; i++)
#define FORD(i, a, b)               for(int i=a; i>=b; i--)
#define MP                          make_pair
#define PB                          push_back
#define ff                          first
#define ss                          second
#define deb(X)                      X;
#define SIZE(coll) 					((int)coll.size())

#define M 1000000007
#define INF 1000000007LL

using namespace std;

long long n, k, best, a, b;
vector <pair<long long, long long>> v;
long long best_col[1000007], pom_col[1000007];
vector <long long> kolory[1000007];

int solve()
{
    cin >> n >> k;
    forr(i, n)
    {
        cin >> a >> b;
        kolory[a].PB(b);
    }
    //sort(v.begin(), v.end(), greater<pair<long long, long long>>());

    FORD(h, 500'000, 1)
    {
        long long pom_best = best;
        for(auto col : kolory[h])
        {
            pom_col[col] = max(best + h - k, best_col[col] + h);
            pom_best = max(pom_best, pom_col[col]);
        }
        best = pom_best;
        for(auto col : kolory[h])
        {
            best_col[col] = max(best_col[col], pom_col[col]);
        }


        /*
        long long h = p.ff;
        long long col = p.ss;

        auto res = max(best + h - k, best_col[col] + h);
        best_col[col] = max(best_col[col], res);
        best = max(best, res);
        */
    }

    cout << best << '\n';

    return 0;
}

int main()
{
    std::ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    solve();

    return 0;
}