Install Composer to my server web

I want install a libraty (PHPMailer) but i don't have composer in my server. And I have an error in the installation. (installation by SSH).

bash-4.2$ curl -sS http://ift.tt/SI3ujS | php
bash: php: command not found
curl: (77) Problem with the SSL CA cert (path? access rights?)

Can you help me ? thanks