#include<bits/stdc++.h>
using namespace std;
int a[2525], d[2525];

int main(){

    int n; cin >> n; for(int i = 0; i < n; i++) cin >> a[i];
    for(int i = 0; i < n; i++){
        int last = a[i];
        d[i] = max(d[i], d[i-1]);
        for(int j = i+1; j < n; j++){
            last = a[j]-last;
            if(last < 0) break;
            if(!last) d[j] = d[i-1]+1;
        }
    }
    cout << n-d[n-1];
}