#include<bits/stdc++.h>
#define REP(i,n) for(int i=0;i<(n);i++)
#define ALL(v) (v).begin(),(v).end()
#define INF 1e18
#define SIZE 100005

using namespace std;
typedef pair<int,int> P;

//-----------------------------------------------------------------------


signed main()
{   
    int a,b; cin>>a>>b;
    string s,t; cin>>s;
    t=s.substr(4);

    double d;
    if(s[3]=='-'){
        if(t.size()==1) d=t[0]-'0';
        if(t.size()==2) d=(t[0]-'0')*10+(t[1]-'0');
        if(t.size()==3) d=(t[0]-'0')+(double)(t[2]-'0')/10;
        if(t.size()==4) d=(t[0]-'0')*10+(t[1]-'0')+(double)(t[3]-'0')/10;
        d=24-d;
    }
    else{
        if(t.size()==1) d=t[0]-'0';
        if(t.size()==2) d=(t[0]-'0')*10+(t[1]-'0');
        if(t.size()==3) d=(t[0]-'0')+(double)(t[2]-'0')/10;
        if(t.size()==4) d=(t[0]-'0')*10+(t[1]-'0')+(double)(t[3]-'0')/10;
    }

    int dh=(int)(d*60)/60;
    int dm=(int)(d*60)%60;
    b+=dm; if(b>=60) b-=60,a++;
    a=(a+dh+15)%24;

    printf("%02d:%02d\n",a,b);
    
}