#include <iostream>
#include <cmath>
using namespace std;
int x, y;
int a, b, c, d;
double s = 0;
int main()
{
cin >> x >> y;
while (cin >> a >> b >> c >> d)
s += sqrt(pow(a - c, 2) + pow(b - d, 2));
s /= 1000;
s *= 2;
int h = s / 20;
int m = round((s / 20 - h) * 60);
// cout<<h<<":"<<m;
printf("%d:%02d", h, m);
return 0;
}