#include <iostream>
#include <sstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <climits>
#include <cfloat>
using namespace std;

int main()
{
    int table[][7] = {{0, 300, 500, 600, 700, 1350, 1650},
                      {6, 0, 350, 450, 600, 1150, 1500},
                      {13, 7, 0, 250, 400, 1000, 1350},
                      {18, 12, 5, 0, 250, 850, 1300},
                      {23, 17, 10, 5, 0, 600, 1150},
                      {43, 37, 30, 25, 20, 0, 500},
                      {58, 52, 45, 40, 35, 15, 0}};
    int a = 17 * 60 + 30;
    int b = 19 * 60 + 30;

    for(;;){
        int ic[2];
        bool half = false;
        for(int i=0; i<2; ++i){
            int h, m;
            cin >> ic[i] >> h >> m;
            if(ic[i] == 0)
                return 0;
            -- ic[i];

            m += h * 60;
            if(a <= m && m <= b)
                half = true;
        }
        if(ic[1] < ic[0])
            swap(ic[0], ic[1]);

        if(table[ic[1]][ic[0]] <= 40)
            half &= true;

        if(half){
            int a = table[ic[0]][ic[1]];
            if(a % 100 != 0)
                a += 50;
            cout << (a / 2) << endl;
        }else{
            cout << table[ic[0]][ic[1]] << endl;
        }
    }
}