Why WA1 ???
Even if replace cw and ccw. The same with lowermost (3) point.
Help me pleace. What with my output?

#include <iostream>
using namespace std;

int main()
{
    int n;
    int x1, y1;
    int x, y;
    int Oldx, Oldy;

    cin >> n;

    cin >> x1 >> y1;

    Oldx=x1;
    Oldy=y1;

    double sum = 0;

    for(int i=2; i<=n; ++i)
    {
        scanf("%d %d", &x, &y);
        sum += (Oldx*(double)y-x*(double)Oldy);
        Oldx=x;
        Oldy=y;
    }

    sum += (x*(double)y1-x1*(double)y);

    if(sum)
        cout << "cw";
    else
        cout << "ccw";


    return 0;
}