```
class Solution(object):
def evalRPN(self, tokens):
"""
:type tokens: List[str]
:rtype: int
"""
ops = {'+': lambda x,y: x+y, '-': lambda x,y: x-y, '*': lambda x,y: x*y, '/': lambda x,y: x/y if x*y>=0 else -(abs(x)/abs(y))}
stack = []
for x in tokens:
if x in ops:
second = stack.pop()
first = stack.pop()
stack.append(ops[x](first, second))
else:
stack.append(int(x))
return stack[0]
```