정올 조약돌

N = int(input())
p = [*map(int,input().split())]
dp = [0]*N

for i in range(N):
    dp[i] = max(dp[i],dp[i-1])
    x = p[i]
    for j in range(i+1,N):
        x = p[j]-x
        if x < 0:
            break
        elif x == 0:
            dp[j] = max(dp[j],dp[i-1]+1)
            break
print(N-dp[-1])