#include <fstream>
using namespace std;
ifstream fin (“ceas.in”);
ofstream fout (“ceas.out”);
int main()
{
long long int a,b,c,d,e;
cin>>a>>b>>c>>d;
e=60*c+d;
if(a==12)
a=0;
while(e>0)
{
if (5*a==b)
{
e-=6;
if(e>=0) b=b+1;
}
else
{
e—;
b=b+1;
}
}