def intreverse(n):
ans = 0
while n > 0:
(d,n) = (n%10,n
ans = 10*ans + d
return(ans)
def matched(s):
nested = 0
for i in range(0,len(s)):
if s[i] == "(":
nested = nested+1
elif s[i] == ")":
nested = nested-1
if nested < 0:
return(False)
return(nested == 0)
def factors(n):
factorlist = []
for i in range(1,n+1):
if n%i == 0:
factorlist = factorlist + [i]
return(factorlist)
def isprime(n):
return(factors(n) == [1,n])
def sumprimes(l):
sum = 0
for i in range(0,len(l)):
if isprime(l[i]):
sum = sum+l[i]
return(sum)