print((function (h0, m0, d, d0)
	local t=d:sub(-2,-2)=="." and
		(h0-d0+tonumber(d:sub(1,-3)))*60+m0+tonumber(d:sub(1,1)..d:sub(-1))*6 or
		(h0-d0+tonumber(d))*60+m0
	local h,m=math.floor(t/60)%24,t%60
	return string.format("%02.0f:%02.0f",h,m)
end)(io.stdin:read("*n"), io.stdin:read("*n"), io.stdin:read("*l"):match("([%+%-%.%d]+)"), 9))