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
#include <bits/stdc++.h>

using namespace std;

typedef vector<int> VI;
typedef long long LL;
#define FOR(x, b, e) for(int x = b; x<= (e); ++x)
#define FORD(x, b, e) for(int x = b; x>= (e); --x)
#define REP(x, n) for(int x = 0; x<(n); ++x)
#define VAR(v, n)typeof(n) v = (n)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
#define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define PB pushback
#define ST first
#define ND second

const int C = 1000000;

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

    int n;
    cin >> n;

    int r, w, t;
    int A[2*C], B[2*C];
    FOR(i, 0, 2*C - 1) {
        A[i] = 0;
        B[i] = 0;
    }
    FOR(i, 1, n) {
        cin >> r >> w >> t;
        if (r == 1) {
            A[w - t + C - 1]++; 
        }
        else {
            B[w - t + C - 1]++; 
        }
    }

    int result = 0;

    FOR(i, 0, 2*C - 1) {
        result += min(A[i], B[i]);
    }

    cout << result << "\n";

    return 0;
}