#include <bits/stdc++.h>

using namespace std;

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = long long;
using P = std::tuple<int,int>;

const int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1}, dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};

int f(string s){
    int sgn = s[3] == '-' ? (-1) : (+1);

    int a = 0;
    for(int i=4;i<s.size();++i){
        if(isdigit(s[i])){
            a = a * 10 + (s[i] - '0');
        }else{
            break;
        }
    }

    a *= 10;

    if(s[s.size() - 2] == '.'){
        a += *s.rbegin() - '0';
    }

    return sgn * a;
}

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

    int A, B;
    string S;
    std::cin >> A >> B >> S;

    int x = f(S) - 90, t = A * 60 + B, d = 24 * 60;
    int nt = (t + x * 6 % d + d) % d;
    int h = nt / 60, m = nt % 60;

    printf("%02d:%02d\n", h, m);
}