func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, i, sum;     int xx[10005], yy[10005], a[10005];     while (scanf( %d , &n) != EOF) {       sum = 0;       for (i = 0; i <= n; i++) {         scanf( %d %d , &xx[i], &yy[i]);       }       for (i = 0; i < n; i++) {         if (xx[i] == xx[i + 1] && yy[i + 1] > yy[i]) a[i] = 1;         if (xx[i] < xx[i + 1] && yy[i + 1] == yy[i]) a[i] = 2;         if (xx[i] == xx[i + 1] && yy[i + 1] < yy[i]) a[i] = 3;         if (xx[i] > xx[i + 1] && yy[i + 1] == yy[i]) a[i] = 4;       }       for (i = 0; i < n - 1; i++) {         if (a[i] > a[i + 1]) sum++;       }       printf( %d n , sum);     }   }   