#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<(b);++i)
#define erep(i,a,b) for(int i=a;i<=(int)(b);++i)
#define per(i,a,b) for(int i=(a);i>(b);--i)
#define eper(i,a,b) for(int i=(a);i>=b;--i)
#define pb push_back
#define mp make_pair
#define INF (1<<31)-1
#define MOD 1000000007
#define all(x) (x).begin(),(x).end()
#define vii vector<int>
#define vll vector<long long>
using namespace std;
typedef long long ll;
typedef pair<int,int> Pii;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0};
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int lcm(int a,int b){return a/gcd(a, b)*b;}

int a, b;
string s;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
    cin >> a >> b >> s;
    int utc_time = a - 9;
    double utc_munite = b;
    double diff = stod(s.substr(4, s.size()-4));
    if (s[3] == '-') diff = -diff;
    utc_time += (int)floor(diff);
    utc_munite += 60.0 * (diff - floor(diff));
    if (utc_munite > 59) {
        utc_time += utc_munite / 60;
    }

    if (utc_time < 0) {
        utc_time = 24 + utc_time;
    } else if (23 < utc_time) {
        utc_time -= 24;
    }

    int munite = (int)round(utc_munite) % 60;
    cout << (utc_time < 10 ? "0" + to_string(utc_time) : to_string(utc_time)) << 
        ":" << (munite < 10 ? "0" + to_string(munite) : to_string(munite)) << endl;
    return 0;
}