#include <iostream>
#include <algorithm>
using namespace std;

int main(){
	int s,g,h,m,t,price;
	bool flag;
	int table[7][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   }
	};
	
	while(cin >> s && s){
		flag = false;
		cin >> h >> m ;
		t = h*60 + m;
		if(t >= 17*60+30 && t <= 19*60+30){
			flag = true;
		}
		
		cin >> g;
		
		cin >> h >> m ;
		t = h*60 + m;
		if(t >= 17*60+30 && t <= 19*60+30){
			flag = true;
		}
		s--;g--;
		if(g>s)swap(s,g);
		
		price = table[g][s];
		
		if(flag && table[s][g]<= 40){
			price /=2;
			if(price%50){
				price = price - price%50 + 50;
			}
		}
		cout << price << endl;
	}
}