Rwanda
noun: Rwandan(s)
adjective: Rwandan

Saint Helena
noun: Saint Helenian(s)
adjective: Saint Helenian

Saint Kitts and Nevis
noun: Kittitian(s), Nevisian(s)
adjective: Kittitian, Nevisian

Saint Lucia
noun: Saint Lucian(s)
adjective: Saint Lucian

Saint Pierre and Miquelon
noun: Frenchman(men), Frenchwoman(women)
adjective: French

Saint Vincent and the Grenadines
noun: Saint Vincentian(s) or
Vincentian(s)
adjective: Saint Vincentian or Vincentian

Samoa
noun: Samoan(s)
adjective: Samoan

San Marino
noun: Sammarinese (singular and plural)
adjective: Sammarinese

Sao Tome and Principe
noun: Sao Tomean(s)
adjective: Sao Tomean

Saudi Arabia
noun: Saudi(s)
adjective: Saudi or Saudi Arabian