#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

const int M=24*60;
int x,y,I,N;
string s;

int main(){
	cin>>x>>y>>s;
	N=s.size();
	I=x*60+y;
	int t=0;
	for(int i=4;i<N;i++){
		if(isdigit(s[i])) t=10*t+(s[i]-'0');
		else break;
	}
	t*=60;
	if(s[N-2]=='.') t+=(s[N-1]-'0')*6;
	if(s[3]=='-') t*=-1;
	t-=540;
	I=(I+t+M*M)%M;
	x=I/60,y=I%60;
	if(x<10) cout<<0;
	cout<<x<<':';
	if(y<10) cout<<0;
	cout<<y<<endl;
}