#include "bits/stdc++.h"
#define fastcin {\
    cin.tie(0);\
    ios::sync_with_stdio(false);\
}
using namespace std;

int main() {
    fastcin;
    int a, b, ans;
    std::string S;
    cin >> a >> b >> S;

    S.erase(S.begin(), S.begin()+3);
    int dot = S.find(".");
    int i = 0, f = 0;
    if(dot==-1) i = stoi(S);
    else {
        if(dot==2) {
            i = stoi(S.substr(0, 2));
            f = stoi(S.substr(3, 1));
        } else {
            i = stoi(S.substr(0, 3));
            f = stoi(S.substr(4, 1));
        }
        if(S[0]=='-') f = -f;
    }

    ans = a*60 + b + (i*60 + f*6 - 540);
    if(ans < 0) ans += 24*60;
    else if(ans > 24*60) ans -= 24*60;

    printf("%02d:%02d\n", ans/60, ans%60);

    return 0;
}