var fs = require('fs')
var contents = fs.readFileSync('/dev/stdin', 'utf-8');

var watch = function(str) {
  var n = parseInt(str); 
  var h = math.floor(n / 3600); 
  var m = math.floor((n - 3600 * h) / 60); 
  var s = n % 60; 

return h + ':' + m + ':' + s ; 

}

console.log(watch(content)); 