Task 6

a = input()
b = input().split()
b = list(map(int, b))
aH = int(a[0]+a[1])
aM = int(a[3]+a[4])
xH = aH + int(b[0])
xM = aM + int(b[1])
if xM > 59:
    xM = xM - 60
    xH = xH + 1
if xH > 23:
    xH = xH % 24
if len(str(xH))< 2:
    xH = ('0' + str(xH))
if len(str(xM))< 2:
    xM = '0' + str(xM)
print(str(xH) + ':' + str(xM))