#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;
		}
	}
}