#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    int a, b;
    string s;
    cin >> a >> b >> s;
    vector<int> c(1, 0);
    for(int i = 0; i < s.size(); i++){
        if(s[i] >= '0' && s[i] <= '9'){
            c.back() *= 10;
            c.back() += s[i] - '0';
        }else if(s[i] == '.'){
            c.push_back(0);
        }
    }
    if(count(s.begin(), s.end(), '-')){
        c[0] *= -1;
        if(c.size() >= 2)c[1] *= -1;
    }
    c[0] -= 9;
    int v = 2880 + c[0] * 60 + c[1] * 6;
    v += a * 60 + b;
    v %= 1440;
    printf("%02d:%02d\n", v / 60 % 24, v % 60);
}