#include <iostream>
#include <fstream>

using namespace std;

const char iname[] = "numarare.in";
const char oname[] = "numarare.out";
const int nmax = 100005;

ifstream fin(iname);
ofstream fout(oname);

int N, A[nmax], i, j, k, sol, t;

int main()
{
	fin >> N;
	for(i = 1; i <= N; i ++)
		fin >> A[i];
	for(i = 1; i <= N; i ++)
		for(j = i  ; j <= N ; j ++)
		{
			t = 1;
			for(k = 0; i + k - 1 >= 1 && j - k + 1 >= 1; k ++)
				if(A[i + k] + A[j - k] != A[i + k - 1] + A[j - k + 1])
					t = 0;
			if(t == 1)
				sol ++;
		}
	fout << sol - 1;
	return 0;
}