#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;

const double EPS = 1e-8;

int main(){
  int a, b;
  string s;
  cin >> a >> b >> s;

  double X;
  stringstream ss(s.substr(3));
  ss >> X;
  X -= 9.0;

  int iX = (int)floor(10 * X);

  int Y = (a*60+b) + 6*iX;
  while(Y<0) Y += 24*60;
  while(Y>=24*60) Y -= 24*60;

  printf("%02d:%02d\n", Y/60, Y%60);
  
  return 0;
}