#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  Int a,b;
  string s;
  cin>>a>>b>>s;
  //cout<<a<<":"<<b<<":"<<s<<endl;
  Int x=s[3]=='-';
  s=s.substr(4);
  Int k=0;
  if(s.size()>=2u&&s[1]=='.'){
    k=(s[0]-'0')*10+(s[2]-'0');
  }else if(s.size()>=3u&&s[2]=='.'){    
    k=(s[0]-'0')*100+(s[1]-'0')*10+(s[3]-'0');
  }else{
    k=stoll(s)*10;
  }
  k*=6;
  if(x) k+=9*60;
  else  k-=9*60;
  Int t=a*60+b;
  if(x) t-=k;
  else  t+=k;
  t%=24*60;
  t+=24*60;
  t%=24*60;
  Int c=t/60,d=t%60;
  cout<<setfill('0')<<setw(2)<<c<<":"<<setfill('0')<<setw(2)<<d<<endl;
  return 0;
}