我哪里错了？？？

#include <bits/stdc++.h>
#define rep(i,a,n,r) for(int (i)=(a);(i)<=(n);(i)+=(r))
#define pre(i,a,n,r) for(int (i)=(a);(i)>=(n);(i)-=(r))
#define ull unsigned long long
#define ui unsigned int
#define int long long
using namespace std;
const int N=2e5+10;
int n,a[N],b[N];
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	int n,mx=-10000;
	cin>>n;
	rep(i,1,n,1){
		cin>>a[i];
		b[i]=b[i-1]+a[i];
	}
	rep(i,1,n,1){
		rep(j,i,n,1){
			mx=max(mx,(b[j]-b[i]));
		}
	}
	cout<<mx;
	return 0; 
}