102.cpp

#include <iostream>
#include <sstream>
#include <algorithm>
#include <iterator>
#include <vector>
#include <deque>
#include <set>
#include <cmath>
using namespace std;

#define REP(i,n) for(int i=0;i<(n);++i)
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
typedef long long LL;

#define MAXN 1000
#define offset 10000
#define eps 1e-8
#define zero(x) (((x)>0?(x):-(x))<eps)
#define _sign(x) ((x)>eps?1:((x)<-eps?2:0))

struct point{double x,y;};
struct line{point a,b;};

double xmult(point p1,point p2,point p0){
	return (p1.x-p0.x)*(p2.y-p0.y)-(p2.x-p0.x)*(p1.y-p0.y);
}

int inside_convex(point q,int n,point* p){
	int i,s[3]={1,1,1};
	for (i=0;i<n&&s[1]|s[2];i++)
		s[_sign(xmult(p[(i+1)%n],q,p[i]))]=0;
	return s[1]|s[2];
}

int inside_convex_v2(point q,int n,point* p){
	int i,s[3]={1,1,1};
	for (i=0;i<n&&s[0]&&s[1]|s[2];i++)
		s[_sign(xmult(p[(i+1)%n],q,p[i]))]=0;
	return s[0]&&s[1]|s[2];
}

vector<string> split( const string& s, const string& delim =" " ) {
    vector<string> res;
    string t;
    for ( int i = 0 ; i != s.size() ; i++ ) {
        if ( delim.find( s[i] ) != string::npos ) {
            if ( !t.empty() ) {
	res.push_back( t );
	t = "";
            }
        } else {
            t += s[i];
        }
    }
    if (!t.empty() ) {
        res.push_back(t);
    }
    return res;
}

vector<int> splitInt( const string& s, const string& delim =" " ) {
    vector<string> tok = split( s, delim );
    vector<int> res;
    for ( int i = 0 ; i != tok.size(); i++ )
        res.push_back( atoi( tok[i].c_str() ) );
    return res;
}

LL gcd(LL a,LL b){
    return b?gcd(b,a%b):a;
}

inline LL lcm(LL a,LL b){
    return a/gcd(a,b)*b;
}

int s2i(string s) {
    stringstream ss;
    ss << s;
    int res;
    ss >> res;
    return res;
}

string i2s(int n) {
    stringstream ss;
    ss << n;
    string res;
    ss >> res;
    return res;
}

void run() {
    point z;
    z.x = z.y = 0;
    point p[3];
    int res = 0;
    REP(i,1000) {
        string str;
        cin >> str;
        vector<int> mm = splitInt(str, ",");
        REP(j,3) {
            p[j].x = mm[j * 2];
            p[j].y = mm[j * 2 + 1];
        }
        if (inside_convex_v2(z, 3, p)) ++res;
    }
    cout << res << endl;
}

int main() {
    run();
}