#include<bits/stdc++.h>//偏差约2s/min
#include<windows.h>
using namespace std;
int m;
int main()
{
    while(1)
    {
        printf("%02d:%02d:%02d",m/3600,m%3600/60,m%60);
        Sleep(1000);
        system("cls");
        m++;
    }
    return 0;
}