function permute(n,r) {
		var result = 1;
		var i;
		for (i = n; i > (n-r); i-- ) {
			result *= i;
		}
		return result;
	}

	function combine(n,r) {
		var result = permute(n,r);
		var divisor = 1;
		var i;
		for ( i = 1; i <= r; i++ ) {
			divisor *= i;
		}
		result /= divisor;
		return result;
	}