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
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
//Krzysztof Pieprzak
#include <bits/stdc++.h>
#include "message.h"
#include "sabotaz.h"

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int,int> pii;
typedef pair<long long, long long> pll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;

#define Size(x) (int)x.size()
#define VAR(v,n) auto v = (n)
#define FOR(i,a,b) for(VAR(i,a); i < (b); ++i)
#define FORE(i,a,b) for(VAR(i,a); i <= (b); ++i)
#define FORREV(i,a,b) for(VAR(i,b); i >= (a); --i)
#define FORSTEP(i,a,b,step) for(VAR(i,a); i < (b); i += (step))
#define FOREACH(i,c) for(VAR(i,(c).begin()); i != (c).end(); ++i)
#define FOREACHS(i,c,n) for(VAR(i,&(c)[0]); i-(c)<(n); ++i)
#define ALL(x) x.begin(),x.end()
#define CLEAR(t) memset(t, 0, sizeof(t))
#define F first
#define S second
#define MP make_pair
#define PUB push_back
#define POB pop_back
#define pieprzu ios_base::sync_with_stdio(0);

const int    INF = 1000000001;
const double EPS = 10e-9;

const int MAXN = 200000;

vi t[MAXN+5];
int d[MAXN+5];
pii st[MAXN+5];
int low[MAXN+5];
int fatCnt[MAXN+5];

int dfs(int v) {
    int dd = 1;
    int pt = 0;
    int n;
    st[0] = MP(v,-1);
    int res = 0;
    while (pt > -1) {
        if (!d[st[pt].F]) low[st[pt].F] = d[st[pt].F] = dd++;
        n = Size(t[st[pt].F]);
        for (++st[pt].S; st[pt].S < n && d[t[st[pt].F][st[pt].S]]; ++st[pt].S)
            if (pt > 0) {
                if (t[st[pt].F][st[pt].S] != st[pt-1].F)
                    low[st[pt].F] = min(low[st[pt].F], d[t[st[pt].F][st[pt].S]]);
                else
                    ++fatCnt[st[pt].F];
            }
        if (st[pt].S != n) {
            st[pt+1] = MP(t[st[pt].F][st[pt].S], -1);
            ++pt;
        }
        else {
            if (low[st[pt].F] == d[st[pt].F] && fatCnt[st[pt].F] == 1) ++res;
            if (pt > 0) low[st[pt-1].F] = min(low[st[pt-1].F], low[st[pt].F]);
            --pt;
        }
    }

    return res;
}

void rob(int test) {
    int n = NumberOfIsles();
    int m = NumberOfBridges();

    int a, b;
    FOR (i, 0, m) {
        a = BridgeEndA(i);
        b = BridgeEndB(i);
        if (a != b) {
            t[a].PUB(b);
            t[b].PUB(a);
        }
    }

    int res = 0;
    FOR (v, 0, n)
        if (!d[v])
            res += dfs(v);

    printf("%d\n", res);
}

int main() {
    int test = 1;
    //scanf("%d", &test);

    if (MyNodeId() != 0)
        return 0;

    FORE (i, 1, test) rob(i);

    return 0;
}