t = list(map(int,input().split(':')))
h, m = t[0],t[1]

if m >= 55 and h == 23:
    h = 0
    m = (m - 55)
    h,m = str(h), str(m)
elif m >= 55:
    h += 1
    m = (m - 55)
    h,m = str(h), str(m)
else:
    m += 5
    h,m = str(h), str(m)
print(f"{h.zfill(2)}:{m.zfill(2)}")