#include <iostream>
using namespace std;
int main()
{
int v[100], n, i;
int x, y, z;
cin>>n;
for(i=1;i<=n;i++)
{
cin>>v[i];
}
for(i=2;i<=n-1;i++)
{
for(int j=1;j<=20;j++)
{
if(v[i-1] + j == v[i] && v[i] + j == v[i+1])
{
x = v[i-1];
y = v[i];
z = v[i+1];
cout<<x<<" "<<y<<" "<<z;
}
}
}
}
Ceva de genul. Dar poti mari la j<=20 la cat vrei tu..