N = int(input())
A = list(map(int, input().split()))

vals = [(a, i) for i, a in enumerate(sorted(A))]

ans = 0
pairs = []

for idx in range(N):
	al, il = vals[idx]
	ar, ir = vals[~idx]
	ans += ar - al
	pairs.append((il + 1, ir + 1))

print(ans)
for i, j in pairs:
	print(i, j)