#include <cstdio>
#include <set>
#include <iostream>
#include <cmath>

using namespace std;

int n;
int F[5010];
set < int > S;

int main ( void ){
    
    scanf( "%d", &n );
    
    for( int i = 0; i < n; ++i ){
         scanf( "%d", F + i );
    }
    
    for( int i = 1; i < n; ++i ){
         S.insert( abs((double)(F[i] - F[i-1])) );
    }
    
    printf( "%d\n", S.size() );  
    
    
    return 0;   
}