#include<algorithm>
#include<iostream>
#include<sstream>
#include<vector>
#include<cmath>
using namespace std;
typedef long long lint;
typedef vector<int>vi;
typedef pair<int,int>pii;
#define rep(i,n)for(int i=0;i<(int)(n);++i)

int main(){
  int a,b;
  string s;
  cin>>a>>b>>s;
  stringstream st(s.substr(3));
  double t;st>>t;
  int diff=floor(t*60+0.5);
  int c=60*a+b+diff+15*60;
  c%=1440;
  printf("%02d:%02d\n",c/60,c%60);
}