#include<iostream>

#include<cstring>

#include<cmath>

#include<algorithm>

#include<cstdio>

#include<map>

#include<queue>

using namespace std;

struct X

{

    long long hh,mm,ss;

    long long len;

    long long st,ml;

}s[+];

int n,k;

long long win[];

bool cmp(const X&a,const X&b)

{

    return a.st<b.st;

}

int main()

{

    scanf("%d%d",&n,&k);

    for(int i=;i<=n;i++)

    {

        scanf("%lld:%lld:%lld %lld",&s[i].hh,&s[i].mm,&s[i].ss,&s[i].len);

        s[i].st=s[i].hh**+s[i].mm*+s[i].ss;

        s[i].len=s[i].len*;

    }

    sort(s+,s++n,cmp);

    for(int i=;i<=k;i++) win[i]=**;

    int i;

    int cnt=;

    for(int i=;i<=n;i++)

    {

        long long Min=;

        if(s[i].st>**) break;

        cnt++;

        for(int j=;j<=k;j++) Min=min(Min,win[j]);

        for(int j=;j<=k;j++)

        {

            if(win[j]==Min)

            {

                s[i].ml=max(win[j],s[i].st);

                win[j]=s[i].ml+s[i].len;

                break;

            }

        }

    }

    long long sum=;

    for(int k=;k<=cnt;k++) sum=sum+s[k].ml-s[k].st;

    if(cnt!=) printf("%.1f\n",1.0*sum//cnt);

    else printf("0.0\n");

    return ;

}