/*
TASK:CROSSING
LANG:C++
*/
#include <iostream>
#include <cmath>
//#include <stdio.h>
using namespace std;
double w,s,a,b;
int hours,minutes,seconds,path;
int main()
{double akm,bkm;
 cin>>w>>s>>a>>b;
 akm=((a*100)*1000)/3600;
 bkm=((b*100)*1000)/3600;
 path=ceil(((w*100)*1000)/akm+((s*100)*1000)/bkm);
 hours=path/3600;
 path-=hours*3600;
 minutes=path/60;
 path-=minutes*60;
 seconds=path;
 cout<<hours<<':'<<minutes<<':'<<seconds<<endl;
// printf("%d:%d:%d\n",(int)hours,(int)minutes,(int)seconds);
 return 0;
}
