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

signed main(){
    ios::sync_with_stdio(false);
	cin.tie(0);
 
    int a,b;
    string s;
    cin>>a>>b>>s;
    int n=s.size();
    if(n==5){
        int t = (int)s[n-1] - '0';
        a+=t-9;
        a+=24;
        a%=24;
    }
    else if(n==6){
        int t = (int)s[4] - '0';
        t*=10;
        t += (int)s[5] - '0';
        a+=t-9;
        a+=24;
        a%=24;
    }
    else if(n==7){
        int t=(int)s[4]-'0';
        a+=t-9+24;
        a%=24;
        t = (int) s[n-1]-'0';
        t*=6;
        b+=t;
        if(b>=60) a++;
        a%=24;
        b%=60;
    }
    else {
        int t = (int)s[4] - '0';
        t*=10;
        t += (int)s[5] - '0';
        a+=t-9+24;
        a%=24;
        t = (int) s[n-1]-'0';
        t*=6;
        b+=t;
        if(b>=60) a++;
        a%=24;
        b%=60;
    }

    if(a<10){
        cout<<0<<a<<":";
    }
    else cout<<a<<":";
    if(b<10){
        cout<<0<<b<<endl;
    }
    else cout<<b<<endl;
    
}