#include <iostream>
#include <stdio.h>
using namespace std;
int main() {
 char c1[2],c2[2];
 int h,m,ic[2],f[2],i,k;
 int g[7][7]={{0,300,500,600,700,1350,1650}, {300,0,350,450,600,1150,1500}, {500,350,0,250,400,1000,1350},
 {600,450,250,0,250,850,1300}, {700,600,400,250,0,600,1150}, {1350,1150,1000,850,600,0,500},{1650,1500,1350,1300,1150,500,0}};
 while(true) {
	 for (i=0;i<2;i++) {
		 cin >> ic[i];
		 if (ic[i]==0) return 0;
		 ic[i]--;
		 cin >> c1 >> c2;
		 h=(c1[0]-'0')*10+(c1[1]-'0');
		 m=(c2[0]-'0')*10+(c2[1]-'0');
		 f[i]=(h==17 && m>29) || (h==18) || (h==19 && m<31);  
		 }
	 k=g[ic[0]][ic[1]];
	 if(k<1350) 
		 if (f[0]+f[1]>0) k=k % 100>0 ? k/2+25:k/2;
	 cout << k << endl;
 }
return 0;
 }