def minimumDistances(a):
    dist = float('inf')
    for i in range(len(a)):
        if a[i] in a[i+1:]:
            b = a.index(a[i],i+1,len(a))
            dist = min(dist,abs(i-b))
    if dist == float('inf'):
        return -1 
    else:
        return dist