var input = require('fs').readFileSync('/dev/stdin', 'utf8').split(/\n/g);
Array.prototype.uniq = function(){
  tmp = {};tmp_arr = [];
  for( var i=0;i<this.length;i++){tmp[this[i]] = i;}
  for( i in tmp){tmp_arr.push(i);}
  return tmp_arr;
}
var s = input[1].split(/\s/g).uniq();
console.log(s.length === 3 ? "Three" : "Four");

