#include <bits/stdc++.h>
using namespace std;
    
int a[110],n,x,c;
int i;
int main() {
    cin>>n;
    for(i = 0;i < n;i++){
        cin>>x;
        if(a[x] == 0) c++;
        a[x]++;
    }
        
    cout<<c<<endl;
    for(i = 1;i <= 100;i++){
        if(a[i] != 0){
            cout<<i<<" "<<a[i]<<endl;
        }
    }
}
/**************************************************************
	Problem: 1725
	User: linmiaoling
	Language: C++
	Result: Accepted
	Time:47 ms
	Memory:2072 kb
****************************************************************/