#include <cstdio>

int main()
{
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i)
  {
    char c;
    scanf("%c", &c);
    if (c == 'Y')
    {
      puts("Four");
      return 0;
    }
  }
  puts("Three");
  return 0;
}