#include <iostream>
using namespace std;

double h(int h, int m) {
  return h + (double)m / 60;
}

int main() {
  int base[8][8] = {{0,0,0,0,0,0,0,0},
		    {0,0, 300,500,600,700,1350,1650},
		    {0,6, 0,  350,450,600,1150,1500},
		    {0,13,7,  0,  250,400,1000,1350},
		    {0,18,12, 5,  0,  250,850, 1300},
		    {0,23,17, 10, 5,  0,  600, 1150},
		    {0,43,37, 30, 25, 20, 0,   500},
		    {0,58,52, 45, 40, 35, 15,  0}};


  while(1) {
    int s, g;
    int sh, sm;
    int gh, gm;
    cin >> s;
    if(s == 0) break;
    cin >> sh >> sm;
    cin >> g;
    cin >> gh >> gm;
    bool half = false;
    if(h(sh,sm) >= h(17,30) && h(sh,sm) <= h(19,30) && base[g][s] <= 40) {
      half = true;
    }
    else if(h(gh,gm) >= h(17,30) && h(gh,gm) <= h(19,30) && base[g][s] <= 40) {
      half = true;
    }
    if(half) {
      int tmp = (base[s][g] / 2 +50) / 50 * 50;
      cout << tmp << endl;
    } else {
      cout << base[s][g] << endl;
    }
  }
  return 0;
}