模拟

#include <iostream>
#include <cstdio>
using namespace std;
int ct = 0;
int h1, h2, m1, m2, s1, s2;
int main(){
	//freopen("test.in", "r", stdin);
	//freopen("test.out", "w", stdout);
	scanf("%d:%d:%d", &h1, &m1, &s1);
	scanf("%d:%d:%d", &h2, &m2, &s2);
    int h3 = h1, m3 = m1, s3 = s1;
	if(s1 >= 60){
			s1 -= 60;
			m1 ++;
		}if(m1 >= 60){
			m1 -= 60;
			h1 ++;
		}if(h1 >= 24){
			h1 -= 24;
		}
	while(h1 != h2 || m1 != m2 || s1 != s2){
        if(!(s3 == 0 && m3 == 0 && h3 == 0))
		if(s1 == 0 && m1 == 0 && h1 == 0){//特判
			printf("next day\n");
		}
		printf("%02d:%02d:%02d\n", h1, m1, s1);
		s1++;
		if(s1 >= 60){
			s1 -= 60;
			m1 ++;
		}if(m1 >= 60){
			m1 -= 60;
			h1 ++;
		}if(h1 >= 24){
			h1 -= 24;
		}
		ct++;
	}
    if(!(s3 == 0 && m3 == 0 && h3 == 0))
    if(h2 == 0 && m2 == 0 && s2 == 0)
    if(s1 == 0 && m1 == 0 && h1 == 0){
			printf("next day\n");
		}
    printf("%02d:%02d:%02d\n", h1, m1, s1);
	s1++;
	printf("total=%d", ct);
	//fclose(stdin);
	//fclose(stdout);

	return 0;
}