#include <bits/stdc++.h>
using namespace std;
#define fo(i,n) for(i=0;i<n;i++)
#define Fo(i,k,n) for(i=k;k<n?i<n:i>n;k<n?i+=1:i-=1)
#define ll long long
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define clr(x) memset(x, 0, sizeof(x))
#define sortall(x) sort(all(x))
#define tr(it, a) for(auto it = a.begin(); it != a.end(); it++)
#define PI 3.1415926535897932384626
typedef pair<int, int>	pii;
vector<ll> primes;
const int NN = 1e6+1;
int prime[2*NN];
void seive(){
    ll i;
    Fo(i, 1, 2*NN) prime[i] = i;
    for(i=2; i < 2*NN; i++){
        if (prime[i] == i){
            for(ll j = 2*i; j < 2*NN; j += i)
                if (prime[j] == j)
                    prime[j] = i;
            primes.pb(i);
        }
    }
}

typedef ll var;
pair<var, var> extended_gcd(var a, var b){
	bool swp = 0;
	if (a<b) swap(a, b), swp = 1;
	//1 = N*a + M*b
	//returns {N, M}
	vector<var> K;
	var k, r, FF, SS;
	while(1){
		k = a/b;
		r = a - k*b;
		if(r == 1){
			FF = 1, SS = -k;
			reverse(all(K));
			for(int k: K){
				var tem = FF;
				FF = SS;
				SS = tem - SS * k;
			}
			return swp?mp(SS, FF):mp(FF, SS);
		}
		else{
			K.pb(k);
		}
		a = b;
		b = r;
		//{1, k}
	}
}
var solve(var a, var b, var n){
	pair<var, var> ans = extended_gcd(a, n);
	var x = ( ans.F * b ) % n;
	if ( x < 0)
		x += n;
	
	//a*x is b (mod n)
	return x;
	
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int i,n,k,j;
	i = 2;
	seive();
	ll sum = 0;
	ll PO[30];
	PO[0] = 1;
	Fo(j, 1, 20) PO[j] = 10*PO[j-1];
	while(primes[i] < NN){
		int p1 = primes[i];
		int p2 = primes[i+1];
		int r = p2-p1;
		int d = 0;
		int v = p1;
		while(v) v/=10, d++;
		ll a = PO[d];
		sum += solve(a, p2-p1, p2) * a + p1;
		i++;
	}
	cout<<sum<<endl;
	return 0;
}