#include <stdio.h>

char inf1[80],inf2[80],outf[80];
/* No defaults */
FILE *fopen(),*ip1,*ip2,*op;

main(argc,argv) int argc; char *argv[];
{ short prime,dim1,dim2,nmats,i,j,k,n,err;
  if (argc<=4) {err=1; goto error;}
  err=0;
  strcpy(inf1,argv[1]); strcat(inf1,"."); strcpy(inf2,inf1); strcpy(outf,inf1);
  strcat(inf1,argv[2]); strcat(inf2,argv[3]); strcat(outf,argv[4]);
  if ((ip1=fopen(inf1,"r"))==0)
  { fprintf(stderr,"Cannot open %s.\n",inf1); exit(1);}
  if ((ip2=fopen(inf2,"r"))==0)
  { fprintf(stderr,"Cannot open %s.\n",inf2); exit(1);}
  fscanf(ip1,"%hd%hd%hd",&prime,&dim1,&nmats);
  fscanf(ip2,"%hd%hd%hd",&i,&dim2,&k);
  if (prime!=i || nmats!=k)
  { fprintf(stderr,"Two groups have different primes or nmats.\n"); exit(1);}
  op=fopen(outf,"w");
  fprintf(op,"%3d%5d%3d\n",prime,dim1+dim2,nmats);

  for (i=1;i<=nmats;i++)
  { for (j=1;j<=dim1;j++)
    { for (k=1;k<=dim1;k++) { fscanf(ip1,"%hd",&n); fprintf(op,"%4d",n);}
      for (k=1;k<=dim2;k++) fprintf(op,"%4d",0);
      fprintf(op,"\n"); 
    }
    for (j=1;j<=dim2;j++)
    { for (k=1;k<=dim1;k++) fprintf(op,"%4d",0);
      for (k=1;k<=dim2;k++) { fscanf(ip2,"%hd",&n); fprintf(op,"%4d",n);}
      fprintf(op,"\n"); 
    }
  }

error:
  if (err)
  { printf("Usage:    sum gpname inf1 inf2 outf.\n"); exit(1);}
  exit(0);
}