n = int(input())
a = list(map(int,input().split()))
mod = int(1e9+7)

def f(a):
    if len(a) == 1:
        return a[0]
    else:
        u = []
        for i in range(len(a)-1):
            u.append((a[i] + a[i+1])%mod)
        return f(u)

print(f(a)%mod)