754 B | 754 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
BLANK = " "
# inp = input
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def to_t(s):
h, m = map(int, s.split(":"))
return h * 60 + m
def solve():
st, en = map(to_t, input().split())
N, T = mii()
crt = st
day = 0
for i in range(N + 1):
if crt + T >= en:
day += 1
crt = st + T
else:
crt += T
p(day)
p(f"{crt//60:02d}:{crt%60:02d}")
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()