#initial parts. This will be the least extended part,
#but I imagine stuff will be added for some language features
stack=[]
program=input().split()
pop=lambda:stack.pop() if stack else 0
for command in program: #the part that will be the most extended
    if command=="five":
        stack.append(5)
    elif command=="divide":
        stack.append(pop()//pop())
    elif command=="add":
        stack.append(pop()+pop())
print(' '.join(str(i) for i in stack))

{
    "five": lambda: stack.append(5),
    "divide": lambda: stack.append(pop()//pop()),
    "add": stack.append(pop()+pop())
}.get(command, lambda:None)()

if input() == "derp":
    print("Derp")
else:
    print("Nope")

p = subprocess.Popen("derp.py",
stdout = subprocess.PIPE,
stdin = subprocess.PIPE)

p.stdin.write("derp\n")
p.stdin.close()

print p.stdout.readline()

import subprocess
p = subprocess.Popen(["python3", "test.py"],
stdout = subprocess.PIPE,
stdin = subprocess.PIPE)

p.stdin.write(bytes("derp\n"))
p.stdin.close()

print p.stdout.readline()

»  flex --help | head
C:\GnuWin32\bin\flex.exe [-bcdfhilnpstvwBFILTV78+? -C[aefFmr] -ooutput -Pprefix -Sskeleton]
        [--help --version] [file ...]
        -b  generate backing-up information to lex.backup
        -c  do-nothing POSIX option
        -d  turn on debug mode in generated scanner
        -f  generate fast, large scanner
        -h  produce this help message
        -i  generate case-insensitive scanner
        -l  maximal compatibility with original lex
        -n  do-nothing POSIX option

while(1){}

for(;;){}

def f(hash,hasher):
 x=0
 while hasher(x)!=hash:
  x+=1
 return x

def f(a,b):
 x=0
 while b(x)!=a:x+=1
 return x

>>> a = 10
>>> a++
  File "<stdin>", line 1
    a++
      ^
SyntaxError: invalid syntax