#include <cstdio>
#include <cmath>

const int price[7][7] = {
  {-1,300,500,600,700,1350,1650},
  {-1,-1,350,450,600,1150,1500},
  {-1,-1,-1,250,400,1000,1350},
  {-1,-1,-1,-1,250,850,1300},
  {-1,-1,-1,-1,-1,600,1150},
  {-1,-1,-1,-1,-1,-1,500}
};

const int dist[7][7] = {
  {-1,6,13,18,23,43,58},
  {-1,-1,7,12,17,37,52},
  {-1,-1,-1,5,10,30,45},
  {-1,-1,-1,-1,5,25,40},
  {-1,-1,-1,-1,-1,20,35},
  {-1,-1,-1,-1,-1,-1,15}
};

const int start = 17*60 + 30 , end = 19*60 + 30;

int main(){
  int sIC,sh,sm,tIC,th,tm;

  while(scanf("%d" ,&sIC) ,sIC){
    scanf("%d%d" ,&sh ,&sm);
    scanf("%d%d%d" ,&tIC ,&th ,&tm);

    sIC--; tIC--;
    bool ok1 = false,ok2 = false;
    int ssum = sh*60 + sm , tsum = th*60 + tm;

    if((start <= ssum && ssum <= end) ||
	(start <= tsum && tsum <= end)) ok1 = true;

    if(dist[sIC][tIC] <= 40) ok2 = true;
 
    int ans = price[sIC][tIC];
    if(ok1 && ok2){
      ans = (ans / 50 + 1) / 2;
      ans *= 50;
    }
    
    printf("%d\n" ,ans);
  }

  return 0;
}