#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define llong long long

int main() {
    int a, b;
    cin >> a >> b;
    string s;
    cin >> s;

    string utc = ""s;
    double utcval = 1.0;
    rep(i, s.length()) {
        if(i < 3) continue;
        else if(i==3) {
            if(s[i] == '-') utcval = -1.0;
        } else {
            utc += s[i];
        }
    }
    utcval *= stod(utc);
    utcval -= 9.0;
    int minutes = a * 60 + b;
    minutes += (int)(utcval * 60);
    minutes += 1440;
    minutes %= 1440;
    printf("%02d:%02d\n", minutes / 60, minutes % 60);
}