#include <stdio.h>
int main()
{
int a,b,c,d,e,f;
scanf("%d%d%d%d",&a,&b,&c,&d); 
 if(d-b<0){
 	f=d-b+60;
	e=c-a-1; 
 }
 else{
 	f=d-b;
 	e=c-a;
 }
 printf("%d%d",e,f);
return 0;
}