#include <bits/stdc++.h>

using namespace std;

#define DEBUG if(1)
#define MAXN 50500
#define MAX 500
#define MAXL 20
#define MIN -2000000
#define INF (1 << 30)
#define MOD 1000000007
#define s(n) scanf("%d", &n)
#define ss(a,b) scanf("%d %d",&a,&b)
#define pb push_back
#define mp make_pair
#define sz(a) int(a.size())
// #define lli long long int
#define lli unsigned long long int
#define lb long double
#define rep(i,a,n) for (int i=a;i<n;i++)
#define ler(a,n,vec) for(int i=0;i<n;i++)s(a), vec.pb(a)
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> ii;
#define F first
#define S second
//ios_base::sync_with_stdio(false);
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
int ddx[] = {1, 0};
int ddy[] = {1, 1};


int main(){

	int n;
	while(s(n)!=EOF){
		vi vec;
		lli sum = 0;
		lli s[100000];
		for(int i=0;i<n;i++){
			int a;
				cin >> a;
				sum += a;

				if(a!=0)
					vec.pb(a);
		}
		if(sum%3!=0){
			cout << 0 << endl;
			continue;
		}

		s[0] = vec[0];
		for(int i=1;i<n;i++) s[i] = s[i-1] + vec[i];

		lli aux = sum/3, ans = 0;

		int a = 0,b = 1;

		while(a < n){
			int aa = s[b] - s[a];
			if(aa < aux) b++;
			else if(aa > aux) a++;
			else{
				if(binary_search(s+b, s+n, s[b] + aux)) ans++, a++;
				else a++;
			}
			if(a == b) b++;
			if(b == sz(vec)) break;
		}

		cout << ans << endl;
	}

	return 0;
}