Prime Minister Narendra Modi has greeted President Pranab Mukherjee on his birthday today. In a tweet, Mr Modi said, President Mukherjee's long years in public life make him an invaluable asset to the nation. <br/><br/>He said, Mr Mukherjee's wisdom and intelligence have few parallels. The Prime Minister said, Mr Mukherjee has always been a respected leader, with friends and well-wishers across the political spectrum. Mr Modi also prayed for his long and healthy life. Mr Mukherjee turned 80 today.