Why the if statements are not being read in this code?

None of the if statements and not even the while condition are being read and I don't understand why. I even put a print statement before to see if it was right.

potential_contour=[['2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2'], ['2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2'], ['2', '2', '2', '2', '2', '2', '2', '0', '0', '0', '0', '0', '0', '0', '2', '2', '2', '2', '2', '2', '2'], ['2', '2', '2', '2', '2', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '2', '2', '2', '2', '2'], ['2', '2', '2', '2', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '2', '2', '2', '2'], ['2', '2', '2', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '2', '2', '2'], ['2', '2', '2', '0', '0', '0', '0', '0', '0', '1', '1', '1', '0', '0', '0', '0', '0', '0', '2', '2', '2'], ['2', '2', '0', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '0', '0', '0', '0', '0', '2', '2'], ['2', '2', '0', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '0', '0', '0', '0', '0', '2', '2'], ['2', '2', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '1', '1', '0', '0', '0', '0', '2', '2'], ['2', '2', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '1', '1', '0', '0', '0', '0', '2', '2'], ['2', '2', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '1', '1', '0', '0', '0', '0', '2', '2'], ['2', '2', '0', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '0', '0', '0', '0', '0', '2', '2'], ['2', '2', '0', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '0', '0', '0', '0', '0', '2', '2'], ['2', '2', '2', '0', '0', '0', '0', '0', '0', '1', '1', '1', '0', '0', '0', '0', '0', '0', '2', '2', '2'], ['2', '2', '2', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '2', '2', '2'], ['2', '2', '2', '2', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '2', '2', '2', '2'], ['2', '2', '2', '2', '2', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '2', '2', '2', '2', '2'], ['2', '2', '2', '2', '2', '2', '2', '0', '0', '0', '0', '0', '0', '0', '2', '2', '2', '2', '2', '2', '2'], ['2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2'], ['2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2']]

for initial_x in range(21):
    for initial_y in range(21):
        potential=0
        for _ in range (5):
            x,y= initial_x, initial_y
            print(potential_contour[x][y])
            while(potential_contour[x][y]==0):
                choice=random.randint(0,3)
                if choice==0: x+=1
                elif choice==1: x-=1
                elif choice==2: y+=1
                elif choice==3: y-=1            

            print(potential_contour[x][y])
            if potential_contour[x][y]==1: potential+=100 #or x==box_dim
            elif potential_contour[x][y]==2: potential+=200