#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char *argv[]){
    int hour,minute;
    char timezone[10];
    char tmp[10]={0};
    int h_timezone,m_timezone = 0;
    scanf("%d%d%s",&hour,&minute,timezone);
    hour += 15;
    strncpy(tmp,timezone+3,5);
    h_timezone = atof(tmp);
    m_timezone = atof(tmp)*60-h_timezone*60;
    hour +=h_timezone;
    minute += m_timezone;
    if (minute >= 60)
    {
        hour++;
    }
    if (hour >= 24)
    {
        hour-=24;
    }
    printf("%02d:%02d\n",hour,minute);
    return 0;
}