def solve():
    N=int(input())
    X=list(map(int,input().split()))

    Mod=10**9+7

    T=0
    for x in X:
        T+=x*(x-1)%Mod

    M=sum(X)
    return (M-T*pow(M, Mod-2, Mod))%Mod

#==================================================
print(solve())