# Test case 1
{a}
{-1}
# Test case 2
{a{b{c}{d{e}}}{f{g}{h{i{j}{k}}}}{l{m}}}
{3,2,3,12,9,7,7,8,9,12,11,12,-1}
# Test case 3 - a path
{{{{{{{{{{{{{{{{{{{{}}}}}}}}}}}}}}}}}}}}
{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,-1}
# Test case 4 - right-branch tree
{{}{{}{{}{{}{{}{}}}}}}
{10,9,8,7,6,6,7,8,9,10,-1}
# Test case 5 - left-branch tree
{{{{{{}{}}{}}{}}{}}{}}
{2,2,4,4,6,6,8,8,10,10,-1}
# Test case 6
{f{a}{e{c{b}}{d}}}
{5,2,4,4,5,-1}