#include<bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
using namespace std;
typedef long long ll;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;
int parse(string S){
    int num = 0;
    bool flag = 0;
    for(auto c:S){
        if(c == '.')flag = 1;
        else if(flag){
            num += (c - '0') * 6;
        }else{
            num *= 10;
            num += (c - '0') * 60;
        }
    }
    return num;
}
main(){
    int a,b;
    string S;
    cin >> a >> b >> S;
    int time = a * 60 + b;
    //int dif = (int)(stof(S.substr(3) ) * 60);
    int dif = parse(S.substr(4));
    if(S[3] == '-')dif *= -1;
    time += dif - 60*9;
    time = (time + 60*24) % (60*24);
    printf("%02d:%02d\n" ,time/60 ,time%60);
}