#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define REP(i, n) rep(i, 0, n)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
using namespace std;
typedef pair<int, int> P;
const int mod = 1000000007;

signed main(){
    int a, b;
    string s;
    cin >> a >> b >> s;
    s = s.substr(3);
    bool f = true;
    if(s[0] == '-') f = false;
    s = s.substr(1);
    int tmp = s[0] - '0';
    s = s.substr(1);
    if(s != "" && isdigit(s[0])){
        tmp = tmp * 10 + s[0] - '0';
        s = s.substr(1);
    }
    tmp *= 60;
    if(s != "" && s[0] == '.'){
        tmp = tmp + 6 * (s[1] - '0');
    }
    if(f == false) tmp *= -1;
    tmp = (tmp - 540 + 60 * 24) % (60 * 24);
    b += tmp % 60;
    a += tmp / 60;
    if(b >= 60){
        a++;
        b %= 60;
    }
    a %= 24;
    printf("%02d:%02d\n", a, b);
}