#include <stdio.h>int main () {
int hour1,minute1;
int hour2,minute2;
scanf("%d %d",&hour1,&minute1);
scanf("%d %d",&hour2,&minute2);
int ih = hour2 - hour1;
int im = minute2 - minute1;
if(im<0){
im = 60 +im;
ih--;
}
printf("时间差事%d小时%d分。\n",ih,im);
return0;
}