def minimumDistances(a):
  count = dict(Counter(a))
  d = []
  for k,v in count.items():
    if v>1:
      d.append(k)
  if(d==[]):
    return -1
  else:
    zz = []
    ret_distance = len(a)
    for x in d:
      zz.append([ i==x for i in a])
      flag = True
      for i in range(len(zz)):
        c_index = -1
        for j in range(len(zz[i])):
          if zz[i][j]==True:
            if(c_index < 0): 
              c_index = j
            else:
              if (j-c_index)<ret_distance:
                ret_distance = j-c_index
              c_index = j
  return(ret_distance)