/*
# 问题分析
题设设定, 给定一组数, 要求计算每一个数与它的序号的差值, 给出重复的差值以及重复的次数, 。
于是我们明白我们要做的是计算+统计.
 
# 完整步骤描述
1. 获取输入: 一组数
2. 初始化统计器:
    - 差值重复的次数 = {0}
3. 对于每一个数:
    - 计算差值 = 绝对值(数值 - 数值序号)
    - 差值重复次数统计器[差值] += 1
4. 对于统计器中的差值从大到小:
    - 输出(差值, 重复的次数)
 
# 伪代码描述
1. get input: numbers
2. init recorder:
    - difference_frequency = {0}
3. for sequence_no, number in numbers:
    - calculate difference = abs(number - sequence_no);
    - difference_frequency[difference] += 1;
4. for difference in sorted_differences_descendingly:
    - print("{difference} {difference_frequency[difference]}");
*/
 
 
# include<stdio.h>
# include<math.h>
 
int main(){
    int card_amount;
    scanf("%d", &card_amount);
    
    int difference_frequency[10010] = {0};
    int number_in_back;
    for (int i = 0; i < card_amount; i++){
        scanf("%d", &number_in_back);
        difference_frequency[abs(number_in_back - (i+1))]++;
    }
    
    for (int i = 10000; i >= 0; i--){
        if (difference_frequency[i] > 1){
            printf("%d %d\n", i, difference_frequency[i]);
        }
    }
    return 0;
}