func_code_string: #include <bits/stdc++.h>   using namespace std;   const int64_t MAXN = 1000000007;   struct point {     int64_t x = 0;     int64_t y = 0;     point(const int64_t& x, const int64_t& y) : x(x), y(y) {}     static point read() {       int64_t x, y;       cin >> x >> y;       return point(x, y);     }   };   double distance(const int64_t& x1, const int64_t& y1, const int64_t& x2,                   const int64_t& y2) {     return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));   }   signed main() {     int64_t n, k;     cin >> n >> k;     double total = 0.0;     int64_t x1, y1;     int64_t x2, y2;     cin >> x1 >> y1;     while (--n) {       cin >> x2 >> y2;       total += distance(x1, y1, x2, y2);       x1 = x2;       y1 = y2;     }     total = total * k / 50;     printf( %.6f , total);     return 0;   }   