Welcome to MPI
The number of processes :: 10
process ID :: 0	Hello, world
process ID :: 1	Hello back
process ID :: 2	Hello back
process ID :: 3	Hello back
process ID :: 4	Hello back
process ID :: 5	Hello back
process ID :: 6	Hello back
process ID :: 8	Hello back
process ID :: 7	Hello back
process ID :: 9	Hello back