#include <bits/stdc++.h>
#define int long long 
#define pii pair<int,int>
#define fi first
#define se second
#define mk make_pair
const int N=10005,inf=1ll<<60;
using namespace std;
int n,k,a[N],v[N],maxn[N],dis[N],rev[N],cnt[N];
struct edge{int x,y,z;};
vector<edge>ans;
signed main()
{
	freopen("meow1.in","r",stdin);
//	freopen("meow.out","w",stdout);
	ios::sync_with_stdio(false);cin.tie(0);
	cin>>n>>k;
	for(int i=2;i<=n;i++)dis[i]=inf;
	for(int i=1;i<=k;i++)cin>>a[i],maxn[a[i]]=i;
	for(int i=1;i<=n;i++)v[maxn[i]]=1;
	for(int l=1,r=1;l<k;l=r+1)
	{
		r=l+1;
		while(!v[r])r++;
		cerr<<l<<' '<<r<<'\n';
		for(int i=l;i<=r;i++)
		{
			if(cnt[a[i]]>0){cout<<"No\n";return 0;}
			cnt[a[i]]++;
		}
		for(int i=l;i<=r;i++)cnt[a[i]]=0;
		for(int i=l+1;i<r;i++)
		{
			dis[a[i]]--;rev[a[i]]=inf-dis[a[i]];
			ans.emplace_back((edge){a[l],a[i],dis[a[i]]-dis[a[l]]});
		}
		ans.emplace_back((edge){a[l],a[r],rev[a[l]]});
		dis[a[r]]=dis[a[l]]+rev[a[l]];
		r--;
    }
    cout<<ans.size()<<'\n';
    for(auto i:ans)cout<<i.x<<' '<<i.y<<' '<<i.z<<'\n';
}