#include <iostream>
#include <iomanip>
#include <string>
#include <cstdio>
#include <cmath>

#define f(i,beg,end) for(int i=beg; i<=end; i++)

using namespace std;

int n;

void redirect()
{
    //freopen("test.txt","r",stdin);
    freopen("sunny.in","r",stdin);
    freopen("sunny.out","w",stdout);
}

void init()
{
    cin >> n;
}

void solve()
{
    string Start, t1, End, t2;
    
    double Temp, ans = 0.0, Time;
    
    f(i,1,n)
    {
        cin >> Start >> t1 >> End >> t2 >> Temp;
        ///cout << Start << " " << t1 << " " << End << " " << t2 << " " << Temp << endl;
        
        int h1, h2, m1, m2;
        h1 = 10*(Start[0]-'0') + (Start[1]-'0');
        h2 = 10*(End[0]-'0') + (End[1]-'0');
        
        m1 = 10*(Start[3]-'0') + (Start[4]-'0');
        m2 = 10*(End[3]-'0') + (End[4]-'0');
        
        //if (t2=="pm" && t1=="am") 
        //    h2+=12;
        
        if (h1==12 && m1==0) 
            if (t1=="am") h1=0;
            else h1=12;
            
        if (h2==12 && m2==0) 
            if (t2=="am") h2=24;
            else h2=12;
            
        //if ( (h1!=12 || m1!=0) && )
        
        int minutes = 60*(h2-h1) + m2-m1;
        
//        if (minutes<0) minutes+=720;
//        if (minutes<0) minutes+=720;
        
        if (t1=="am" && t2=="pm" && (h1!=12 || h2!=12 || m1!=0 || m2!=0)) minutes+=720;
        
        //cout << (double)(minutes/60.0) * Temp * sqrt(Temp) << " " <<  minutes/60.0 << " " << Temp << endl;
        
        //cout << minutes << endl;
        
        double E = (double)(minutes/60.0) * Temp * sqrt(Temp);
        
        ans += E;
        
    }
    
    cout << setprecision(3) << fixed << ans ;//<< endl;
    //printf("%.3f\n",ans);
}

int main()
{
    redirect();
    init();
    solve();
    
    return 0;
}