Started learning python, this is maximum sum subarray i have tried. Ending up with "maximum recursion depth exceeded in comparison". My algorithm seems ok to me. Please help me if im doing anything wrong. 

```
import sys
import math
def maxtuple(lss,rss):
    if lss[2] > rss[2]:
        return lss
    else:
        return rss
def crosssubarray(A, start, mid, end):
    ls=rs=-sys.maxsize
    maxleft=0
    maxright=0
    sum = 0;
    for i in reversed(range(start, mid)):
        sum = sum + A[i]
        print(i)
        if sum > ls:
            ls = sum
            maxleft = i
    sum = 0
    for i in range(mid+1, end):
        sum = sum+ A[i]
        if sum > rs:
            rs = sum
            maxright = i
    return (maxleft, maxright, ls+rs)

def maxsubarray(A,start,end):
    if start == end:
        return (start,end,A[start])
    else:
        mid = (start+end)/2
        lss = maxsubarray(A, start, mid)
        rss = maxsubarray(A, mid+1, end)
        css = crosssubarray(A, start, mid, end)
        maxsub = maxtuple(lss,rss)
        maxall = maxtuple(maxsub, css)
        return maxall

A = [13,-3,-25,20,-3,-16,-23,18,20,-7,12,-5,-22,15,-4,7]
print(maxsubarray(A,0,15))

```