N = 7;
R = 16;
from = [6, 5, 1, 7, 6, 4, 5, 4, 1, 2, 5, 4, 5, 2, 3, 7];
to = [3, 3, 4, 4, 7, 2, 7, 7, 3, 5, 1, 3, 4, 4, 1, 3];
distance = [14, 86, 21, 182, 158, 76, 224, 182, 16, 110, 73, 35, 53, 76, 16, 147];