#include<stdio.h>
int main()
{
	int h1,m1,h2,m2,k;
  	scanf("%d %d %d %d %d",&h1,&m1,&h2,&m2,&k);
  int total=0;
  if(m1<=m2)
  {
    total=(h2-h1)*60+m2-m1;
  }
  else 
  {
    total=(h2-h1)*60-m2+m1;
  }
  printf("%d\n",(total-1)/k);
}