#!/usr/bin/env python3

# Challenge 163
#
# Task 2: Summations
# Submitted by: Mohammad S Anwar
#
# You are given a list of positive numbers, @n.
#
# Write a script to find out the summations as described below.
# Example 1
#
# Input: @n = (1, 2, 3, 4, 5)
# Output: 42
#
#     1 2 3  4  5
#       2 5  9 14
#         5 14 28
#           14 42
#              42
#
# The nth Row starts with the second element of the (n-1)th row.
# The following element is sum of all elements except first element of previous
# row.
# You stop once you have just one element in the row.
#
# Example 2
#
# Input: @n = (1, 3, 5, 7, 9)
# Output: 70
#
#     1 3  5  7  9
#       3  8 15 24
#          8 23 47
#            23 70
#               70

import sys
from functools import reduce

def summation(*n):
    n = list(n)
    while len(n) > 1:
        n.pop(0)
        m = []
        for i in range(len(n)):
            m.append(sum(n[:i + 1]))
        n = m
    return n[0]

print(summation(*map(int, sys.argv[1:])))