#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ul = unsigned long;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	int a, b;
	string s;
	cin >> a >> b >> s;

	int t1 = a * 60 + b;

	auto pos = s.find('.');
	int h, m;
	if (pos != string::npos)
	{
		h = stoi(s.substr(4, pos - 3));
		m = stoi(s.substr(pos + 1)) * 6;
	}
	else
	{
		h = stoi(s.substr(4));
		m = 0;
	}
	int t2;
	string op = s.substr(3, 1);
	if (op == "+")
		t2 = 540 - (h * 60 + m);
	else
		t2 = (9 + h) * 60 + m;

	int t = t1 - t2;
	if (t < 0)
		t += 24 * 60;
	int hh = (t / 60 + m / 60) % 24,
		mm = t % 60;
	string res;
	res = (hh < 10 ? "0" : "") + to_string(hh)
		+ ":"
		+ (mm < 10 ? "0" : "") + to_string(mm);
	cout << res << "\n";

	return 0;
}