#include <stdio.h>
#include <mpi.h>

int main (int argc, char **argv) {
  int rank, size;
  int data, reduced;
  MPI_Init (&argc, &argv);
  MPI_Comm_rank (MPI_COMM_WORLD, &rank);
  MPI_Comm_size (MPI_COMM_WORLD, &size);
  
  data = rank + 1;
  MPI_Reduce(&data, &reduced, 1, MPI_INT, MPI_PROD, 0, MPI_COMM_WORLD);
  if(rank == 0) {
    printf("Value reduced: %d\n", reduced);
  }
  
  MPI_Finalize();
  return 0;
}