def decode$($message$\_$file$)$:

with open$($message$\_$file, $\text{'}$r$\text{'})$ as file:

lines $=$ file.readlines$()$

pyramid$\_$end $=[1]$

for i in range$(1,$ len$($lines$))$:

pyramid$\_$end.append$($pyramid$\_$end$[$i$-1]+$ i $+1)$

message $=\text{'}\text{'}$

for i in pyramid$\_$end:

message $+=$ lines$[$i$-1].$split$()[1]+\text{'}\text{'}$

return message.strip$()$