2)
int main () {
int n,v[100],i,suma=0;
cin>>n;
for (i=1;1<=n;i++)
cin>>v[i];
for(i=1;i<=n;i++)
if( i%2==1) suma = suma + v[i] ;
cout<< suma;
return 0; }
3)
int main () {
int n,v[100],i,nule,negative;
cin>>n;
nule=0;
negative=0;
for ( i=1;i<=n;i++ )
cin>> v[i] ;
for ( i=1;i<=n;i++)
{
if ( v[i] == 0 ) nule ++ ;
if ( v[i] < 0 ) negative ++;
}
cout << nule << " '' << negative ;
return 0 ; }
