Issue to restart ES after modify config file

hi
i wish to modify the shard number in ES 1.1.1
i am getting some problem after modifying the config file elasticsearch.yml
i have change that
index.number_of_shards:3
error i have recieved is below
SettingsException[Failed to load settings from [file:/opt/elasticsearch-1.1.1/config/elasticsearch.yml]]
ScannerException[while scanning a simple key; could not found expected ':'; in 'reader', line 111, column 1:
# Set the number of replicas (ad ...
^]

can i help me please