#include<iostream>
#include<iomanip>
#include<math.h>
using namespace std;

int main()
{
	int n;
	cin >> n;
	int back[n + 1];
	for (int i = 1;i < n + 1;i++)
		scanf("%d",&back[i]);
	
	int front[n + 1];
	for (int i = 1;i < n + 1;i++)
		front[i] = i;
	
	int res[n];
	for (int i = 0;i < n;i++)
		res[i] = abs(front[i + 1] - back[i + 1]);
	int ans[10000];
	for (int i = 0;i < 10000;i++)
	{
		ans[i] = 0;
	}
	int count = 0;
	for (int i = 0;i < n;i++)
	{
		ans[res[i]]++;
	}
	for (int i = 9999;i >= 0;i--)
	{
		if (ans[i] > 1)
			cout << i << " " << ans[i] << endl;
	}




	return 0;
}