// Program 11 - Build DNA along a curve
#define RISE    3.38

#define EPS 1e-3
#define APPROX(a,b) (fabs((a)-(b))<=EPS)
#define MAXI    20

#define MAXPTS  150
int npts;
float   a[ MAXPTS ];
float   x[ MAXPTS ], y[ MAXPTS ], z[ MAXPTS ];
float   x2[ MAXPTS ], y2[ MAXPTS ], z2[ MAXPTS ];
float   tmp[ MAXPTS ];

string  line;

int i, li, ni;
float   dx, dy, dz;
float   la, lx, ly, lz, na, nx, ny, nz;
float   d, tfrac, frac;

int spline();
int splint();

for( npts = 0; line = getline( stdin ); ){
    npts = npts + 1;
    a[ npts ] = npts;
    sscanf( line, "%lf %lf %lf",
        x[ npts ], y[ npts ], z[ npts ] );
}

spline( a, x, npts, 1e30, 1e30, x2, tmp );
spline( a, y, npts, 1e30, 1e30, y2, tmp );
spline( a, z, npts, 1e30, 1e30, z2, tmp );

li = 1; la = 1.0; lx = x[1]; ly = y[1]; lz = z[1];
printf( "%8.3f %8.3f %8.3f\n", lx, ly, lz );

while( li < npts ){
    ni = li + 1;
    na = a[ ni ];
    nx = x[ ni ]; ny = y[ ni ]; nz = z[ ni ];
    dx = nx - lx; dy = ny - ly; dz = nz - lz;
    d = sqrt( dx*dx + dy*dy + dz*dz );
    if( d > RISE ){
        tfrac = frac = .5;
        for( i = 1; i <= MAXI; i = i + 1 ){
            na = la + tfrac * ( a[ni] - la );
            splint( a, x, x2, npts, na, nx );
            splint( a, y, y2, npts, na, ny );
            splint( a, z, z2, npts, na, nz );
            dx = nx - lx; dy = ny - ly; dz = nz - lz;
            d = sqrt( dx*dx + dy*dy + dz*dz );
            frac = 0.5 * frac;
            if( APPROX( d, RISE ) )
                break;
            else if( d > RISE )
                tfrac = tfrac - frac;
            else if( d < RISE )
                tfrac = tfrac + frac;
        }
        printf( "%8.3f %8.3f %8.3f\n", nx, ny, nz );
    }else if( d < RISE ){
        li = ni;
        continue;
    }else if( d == RISE ){
        printf( "%8.3f %8.3f %8.3f\n", nx, ny, nz );
        li = ni;
    }
    la = na;
    lx = nx; ly = ny; lz = nz;
}