pivot3 m<nr<nc<ir<jc<v<w<i<mat
L[KK<KK
]0=I::0^m;nr<jc'"(::0$m;nr<jc'"):)/0^m;i[:@1UInr"<jc[-/1GM::nc[-/1URm"_1"Ym;nr[-/1YR:L[mat[m"<''"""
m;v<'[m;v<'_m;v[::ir*Inr"/Inr"<jc'J.=m;ir<'[m;ir<'+m;ir[-/1YHMm;i<nc'+m;i[::0*m;i<jc'"/i"<jc'<jc'
]1,0Rm;v<w'[_mat;v<w[::jc%Inc"/Inc"'=m;ir<jc'[+mat;ir<jc'
