int rsech(p,k,m,a,b)
  STRU p[];
  double  a,b;
  int k,m;
  { int i;
    i=k;
    while ((i<=m)&&((p[i].KEY<a)||(p[i].KEY>b))) i=i+1;
    if (i>m) return(-1);
    return(i);
  }