How to know which frame of trajectory has a minimum energy in free energy landscape analysis?

GROMACS version: 2019

Hi gromacs user,

I obtained the 2D plot of Free energy landscape using PC1 and PC2 from fel.txt file.
I used the following commands:

gmx_mpi covar -f final.xtc -s md.tpr -o eigenvalues.xvg -v eigenvectors.trr -xpma covapic.xpm
gmx_mpi anaeig -v eigenvectors.trr -f final.xtc -s md.tpr -proj pc1.xvg -first 1 -last 1
gmx_mpi anaeig -v eigenvectors.trr -f final.xtc -s md.tpr -proj pc2.xvg -first 2 -last 2
perl sham.pl -i1 pc1.xvg -i2 pc2.xvg -data1 1 -data2 1 -o pc12.xvg
gmx_mpi sham -f pc12.xvg -ls fel.xpm
python xpm2txt.py -f fel.xpm -o fel.txt

How to know which frame has a minimum energy in 2D plot? which command should I use?

Any help will be appreciated.