/*
ID: espr1t
TASK: 
KEYWORDS: 
CONTEST: CodeIT Round 4
*/

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <algorithm>
#include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>

using namespace std;
FILE *in; FILE *out;

const int MAX = 1024;

void fixTime(int& h, int& m, char t) {
    h %= 12;
    if (t == 'p') h += 12;
}

double getTime(int sh, int sm, int eh, int em) {
    if (sh == eh && sm == em) return 1;
    int ans = 0;
    // 23:52 - 02:56 -> 184
    if (sh > eh || (sh == eh && sm > em)) {
        ans += (24 - (sh - eh)) * 60;
    }
    else {
        ans += (eh - sh) * 60;
    }
    // 15:59 - 16:01 -> 2
    // 15:31 - 16:29 -> 58
    if (sm <= em) {
        ans += em - sm;
    }
    else {
        ans -= sm - em;
    }
    return ans;
}

int main(void) {
	in = stdin; out = stdout;
	in = fopen("sunny.in", "rt"); out = fopen("sunny.out", "wt");
	
	double ans = 0.0;
	int n;
	fscanf(in, "%d", &n);
	for (int i = 0; i < n; i++) {
	    int sh, sm; char stm[32];
	    fscanf(in, "%d:%d %s", &sh, &sm, stm);
	    int eh, em; char etm[32];
	    fscanf(in, "%d:%d %s", &eh, &em, etm);
	    double u;
	    fscanf(in, "%lf", &u);
	    
	    fixTime(sh, sm, stm[0]);
	    fixTime(eh, em, etm[0]);
//	    fprintf(stderr, "%02d:%02d to %02d:%02d (%lf minutes) for %lf\n", sh, sm, eh, em, getTime(sh, sm, eh, em), u);
	    ans += getTime(sh, sm, eh, em) / 1440.0 * 24.0 * u * sqrt(u);
	}
	fprintf(out, "%.3lf\n", ans);
	return 0;
}