n=len(s)
i=0
j=-1
if n == 0:
    return s
while i < n-1 :
    if s[i] == ' ':
        i = i + 1
    else:
        #print(s)
        s=s[i:n]
        #print(s)
        break
if i == n-1 :
    return ""

while j > 1-n:
    if s[-1] != ' ':
        break
    if s[j] == ' ':
        j = j - 1
    else:
        s=s[:j+1]
        break
#print(s)
return s