#include <iostream>

using namespace std;

int main()
{
    string time;
    cin >> time;
    int h = (time[0] - '0') * 10 + (time[1] - '0');
    int m = (time[3] - '0') * 10 + time[4] - '0';
    h %= 12;
    double ans = (h * 60 + m) * 0.5 - m * 6;
    if (ans < 0) ans = -ans;
    ans = min(ans, 360 - ans);
    cout << ans;
    return 0;
}