def trim(s):    i,ci,cj = 0,0,0    j = 1    while i < len(s)-1:        if s[i] == ' ':            i += 1            ci += 1        else:            break    while j < len(s):        if s[-j] == ' ':            j += 1            cj += 1        else:            break    if ci>0 and cj>0:        return s[ci:-cj]
    elif ci==0 and cj>0:        return s[:-cj]
    elif ci>0 and cj==0:        return s[ci:]
    else:        return s