#include <bits/stdc++.h> #define rep(i,n) for (int i=0; i<(n); ++i) using namespace std; using ll=long long; int main(){ int a; cin>>a; a*=6; a/=10; int x,y; x=a/60; y=a%60; if(a==600){ cout<<"20:00"<<endl; } else{ if(y<=9){ cout<<"1"<<x<<":"<<"0"<<y<<endl; } else{ cout<<"1"<<x<<":"<<y<<endl; } } }