Codeforces A. Broken Clock

//Next Codeforces Round #354 (Div. 2)
#include<bits/stdc++.h>

//#include<cstdio>
//#include<iostream>
//#include<algorithm>
//#include<vector>
//#include<cstring>
//#include<cmath>
//#include<map>

using namespace std;

#define fast ios_base::sync_with_stdio(false)
#define bfast cin.tie(0)
#define outs(x) cout << x << " "
#define outn(x) cout << x << "\n"
#define sf scanf
#define pf printf
#define nl puts("")

typedef long long LL;
typedef vector<int>vii;
typedef vector<LL>vll;

void twelve(int h , int m, char ch)
{
     bool hf=false, mf=false;
     string uh="10" , um="0";

     if(m>=0 and m<=9)
     {
         um+=char(m+'0');
     }

     else
     {
         um = "";
         string tmp="";
         stringstream ss;
         ss << m;
         ss >> tmp;
         um+=tmp;
     }

     if(h>=1 and h<=9)
     {
         uh="0";
         uh+=char(h+'0');
     }

     else
     {
         uh="";
         //uh+=char(h+'0');
         string tmp="";
         stringstream ss;
         ss << h;
         ss >> tmp;
         uh+=tmp;

         if(uh == "0") uh="10";
     }

     //cout << "uh = " << uh << "\n";

     if(h>=1 and h<=12) hf=true;
     if(m>=0 and m<=59) mf=true;

     if(hf==false and mf==false)
     {
         bool hzero=false;

         if(h==0)
         {
             hzero=true;
             uh="10";
         }

         if(hzero)
         {
             if(m > 0)
             {
                 cout << uh << ch << "0" << m%10 << "\n";
             }

             else
             {
                 cout << uh << ch << um << "\n";
             }
         }

         else
         {
             cout << "0" << h%10 << ch << "0" << m%10 << "\n";
         }
     }

     else if(hf==false and mf==true)
     {
         bool hzero=false;

         if(h==0)
         {
             hzero=true;
             uh="10";
         }

         if(hzero)
         {
             if(m==0)
             {
                 cout << uh << ch << um << "\n";
             }

             else
             {
                 cout << uh << ch << um << "\n";
             }
         }

         else
         {
             if(h%10 == 0)
             {
                 uh="10";

                 cout << uh << ch << um << "\n";
             }

             else
             {
                 cout << "0" << h%10 << ch << um << "\n";
             }
         }
     }

     else if(hf==true and mf==false)
     {
         cout << uh << ch << "0" << m%10 << "\n";
     }

     else if(hf==true and mf==true)
     {
         cout << uh << ch << um << "\n";
     }
}

void twentyfour(int h , int m , char ch)
{
     bool hf=false, mf=false;
     string uh="0" , um="0";

     if(m>=0 and m<=9)
     {
         um+=char(m+'0');
     }

     else
     {
         um = "";
         string tmp="";
         stringstream ss;
         ss << m;
         ss >> tmp;
         um+=tmp;
     }

     if(h>=0 and h<=9)
     {
         uh="0";
         uh+=char(h+'0');
     }

     else
     {
         uh="";
         //uh+=char(h+'0');
         string tmp="";
         stringstream ss;
         ss << h;
         ss >> tmp;
         uh+=tmp;
     }

     //cout << "uh = " << uh << " um= " << um << "\n";

     if(h>=0 and h<=23)hf=true;
     if(m>=0 and m<=59)mf=true;

     if(hf==true and mf==true)
     {
         cout << uh << ch << um << "\n";
     }

     else if(hf==true and mf==false)
     {
         cout << uh << ch << "0" << m%10 << "\n";
     }

     else if(hf==false and mf==true)
     {
         cout << "0" << h%10 << ch << um << "\n";
     }

     else if(hf==false and mf==false)
     {
         cout << "0" << h%10 << ch << "0" << m%10 << "\n";
     }
}

int main()
{
    fast;
    int format , i , h , m;
    string s ;
    while(cin >> format)
    {
        cin >> h >> s[0] >> m;

        if(format == 12)
        {
            twelve(h , m , s[0]);
        }

        else
        {
            twentyfour(h , m , s[0]);
        }
    }

    return 0;
}