#include<stdio.h>
int main(void){
  int hh, mm;
  scanf("%d:%d", &hh, &mm);
  if((hh >= 0 && hh <= 23) && (mm >= 0 && mm <= 59)){
    if(mm + 5 > 59){
      if(hh + 1 > 23){
        hh = 0;
      }else{
        hh = hh +1;
      }
    }else{
      mm = mm + 5;
    }
  }
  printf("%02d:%02d\n", hh, mm);
}