Intereseting C Program

This C program won the first prize in International obfuscated C code
contest (IOCCC) held recently.It is amazing. My friend sent it to me this morning. I felt that, it's better to pass it on to you. Answer is given down. But, try to guess the output yourself before watching the answer down. Here it goes.....

#include
main(t,_,a)
int t;
char _;
char *a;
{return!0