Doubt about iptables rules.

Hello,

On the chain RH-Firewall-1-INPUT, what's the mean of the rules number 1
and 2, please?

"# iptables -L --line-number
Chain INPUT (policy ACCEPT)
num  target     prot opt source               destination
1    RH-Firewall-1-INPUT  all  --  anywhere             anywhere

Chain FORWARD (policy ACCEPT)
num  target     prot opt source               destination
1    RH-Firewall-1-INPUT  all  --  anywhere             anywhere

Chain OUTPUT (policy ACCEPT)
num  target     prot opt source               destination

Chain RH-Firewall-1-INPUT (2 references)
num  target     prot opt source               destination
1    ACCEPT     all  --  anywhere             anywhere
2    ACCEPT     icmp --  anywhere             anywhere            icmp any
"


TIA,
Vinicius.