#include <bits/stdc++.h>
using namespace std;
int a[10000001];
int f[10000001];
int b[10000001];
int main() {
int n,i,j,s=1,m,k,s1,s2;
cin>>n;
f[1]=1;
b[0]=1;
for(i=1;i<=n;i++)
{
cin>>a[i];
if(i>1&&a[i]!=a[i-1])
{s++;
f[s]=i;
}
}
s1=s;
for(i=1;i<=s;i++)
{
b[i]=f[i+1]-f[i];
}
b[s]=n-f[s]+1;
while(s1>0)
{s2=n+1;
for(i=1;i<=s;i++)
{
if(s2==a[f[i]])
{
f[i]=f[i];
}
else
if(b[i]>0)
{
cout<<f[i]<<" ";
s2=a[f[i]];
f[i]++;
b[i]--;
}
else
if(b[i]==0)
{
s1--;
b[i]--;
}
}cout<<endl;
}
}