#include <iostream>
#include <iomanip>
#include <cstring>
#include <algorithm> 
#include <math.h>
#include <queue>
#include <functional>
#include <map>
#include <vector>
#include <string>
using namespace std;

typedef long long ll;
typedef pair<int, int> P;

int dx[] = { 1, 0, -1, 0 };
int dy[] = { 0, 1, 0, -1 };

const ll MOD = 1000000007;
const ll INF = 100000;

int a, b;
string s, sa, sb;
int main(void){
    cin >> sa >> sb >> s;
    a = stoi(sa); b = stoi(sb);
    string s2;
    for (int i = 4; i < s.size(); i++) s2 += s[i];

    int jtime = a * 60 + b;
    int time = (int)(stod(s2) * 60); 
    int ans = 0;

    if (s[3] == '+') ans += jtime + time - 540;
    else ans += jtime - time - 540;

    if (ans < 0)  ans += 1440;
    else ans %= 1440;

    if (ans / 60 < 10) cout << '0';
    cout << ans / 60 << ':';
    if (ans % 60 < 10) cout << '0';
    cout << ans % 60;


}