#define _CRT_SECURE_NO_DEPRECATE
#include <iostream>
#include <string>
#include <vector>
#include <sstream>
#include <ctime>
#include <queue>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <math.h>
#include <stack>
#include <deque>
#include <numeric>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <bitset>

#define all(v) v.begin(),v.end()

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
const ld epsylon = 1e-9;
typedef unsigned int ui;
inline long double get_time(){   
	return (long double)clock()/CLOCKS_PER_SEC;
};


int n;
struct tmm{
	int hh, mm;
	bool pm;
};
int minutes(tmm f, tmm s)
{
	int res = 0;
	tmm tmpf = f, tmps = s;
	if (f.pm) f.hh += 12;
	if (s.pm) s.hh += 12;
	res = (s.hh - f.hh) * 60;
	res += s.mm;
	res -= f.mm;
	return res;
}
double hours(int minutes) {return (double)minutes/60.0;}
tmm days[2][512];
double u[512];
int main()
{
	freopen("sunny.in","r",stdin);
	freopen("sunny.out","w",stdout);
	//program
	scanf("%d\n", &n);
	for (int i = 0; i < n; ++i)
	{
		char d1, d2, h11,h12,h21,h22,m11,m12,m21,m22,tmp;
		scanf("%c%c:%c%c %c%c %c%c:%c%c %c%c %lf\n",&h11,&h12,&m11,&m12,&d1,&tmp,
			&h21,&h22,&m21,&m22,&d2,&tmp, &u[i]);
		days[0][i].hh = 10*(h11-'0');days[0][i].hh += (h12-'0');
		days[0][i].mm = 10*(m11-'0');days[0][i].mm += (m12-'0');
		days[1][i].hh = 10*(h21-'0');days[1][i].hh += (h22-'0');
		days[1][i].mm = 10*(m21-'0');days[1][i].mm += (m22-'0');
		if (d1 == 'a') days[0][i].pm = 0; else days[0][i].pm = 1;
		if (d2 == 'a') days[1][i].pm = 0; else days[1][i].pm = 1;
	}
	double res = 0;
	for (int i = 0; i < n; ++i)
	{
		res += hours(minutes(days[0][i], days[1][i])) * pow(u[i], 1.5);
	}
	printf("%.3lf\n", res);

	//end program
	return 0;
}






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