def isPrime(num):
        if num == 1:
                return False
        for i in range(2, num):
                if num % i == 0:
                        return False
        return True

def maxSum(tri, i, j, size):
        if(i == size or j < 0 or isPrime(int(tri[i][j]))):
                return 0
        res = int(tri[i][j])
        res += max(maxSum(tri, i + 1, j, size), maxSum(tri, i + 1, j + 1, size), maxSum(tri, i + 1, j - 1, size))
        return res

f = open("/content/drive/My Drive/input.txt","r")
text = f.read()
rows = text.split('\n')
pyramid = []

for row in rows:
        currentRow = row.split(' ')
        pyramid.append(currentRow)

print("The maximum sum is ", maxSum(pyramid, 0, 0, len(pyramid)))