diff --git a/README.md b/README.md
index 0de9c70..1ebabf9 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,9 @@ You only need to installl pyOpenSSL:
 
 # Usage
 
-`python ssl_checker.py host1 [host2] [host3]...`
+`python ssl_checker.py host1[:port] [host2:port] [host3:port]...`
+
+Port is optional here. The script will use 443 if not specified.
 
 # Example
 
@@ -29,6 +31,3 @@ Analyzing 3 hosts:
 
 {'archive.org': {'valid_till': '2020-02-21', 'valid_from': '2016-12-19', 'cert_alg': u'sha256WithRSAEncryption', 'cert_ver': 2, 'cert_sn': 17565460289571369468L, 'cert_exp': False, 'issuer_c': u'US', 'issuer_cn': u'Go Daddy Secure Certificate Authority - G2', 'issuer_o': u'GoDaddy.com, Inc.', 'issuer_ou': u'http://certs.godaddy.com/repository/'}, 'cisco.com': {'valid_till': '2019-12-07', 'valid_from': '2017-12-07', 'cert_alg': u'sha256WithRSAEncryption', 'cert_ver': 2, 'cert_sn': 228799876318721608922476410131646115852301898990L, 'cert_exp': False, 'issuer_c': u'US', 'issuer_cn': u'HydrantID SSL ICA G2', 'issuer_o': u'HydrantID (Avalanche Cloud Corporation)', 'issuer_ou': None}}
 ```
-
-
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