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#include<iostream>
#include<cstring>
#include<cmath>
#include<algorithm>

using namespace std;
char ys[9] = {0};
int mgs[3] = {0};//分解每个数
int module = 0;//余数
int x = 0;//三位数真实的  021=21
int s = 0;
bool checkprime(int a) {
    for (int i = 2; i>=0; i--) {
        module = a;
        mgs[i] = a % 10;
        module = a / 10;
    }
    if (mgs[0] != 0) {//百位不为0
        for (int i = 2; i < a; i++) {
            if (a % i == 0) {
                return false;
            }
        }
    }
    else if (mgs[0] == 0) {//百位为0
        if (mgs[1] == 0) {//十位为0
            if (mgs[2] == 0) {//个位为0
                return false;
            }
            else if (mgs[2] == 1) {//个位为1
                return false;
            }
            else {//个位不为1
                for (int i = 2; i < mgs[2]; i++) {
                    if (mgs[2] % i == 0) {
                        return false;
                    }
                }
            }
        }
        else {//百位为0  十不为0
            x = mgs[2] + mgs[1] * 10;
            for (int i = 2; i < x; i++) {
                if (x % i == 0) {
                    return false;
                }
            }
        }
    }
    return true;
}
bool checksqrt(int a) {
    for (int i = 2; i>=0; i--) {
        module = a;
        mgs[i] = a % 10;
        module = a / 10;
    }
    if (mgs[0] != 0) {
        s = sqrt(a);
        if (s * s == a) {
            return true;
        }
        else {
            return false;
        }
    }
    else if (mgs[0] == 0) {
        if (mgs[1] == 0) {
            if (mgs[2] == 0) {
                return false;
            }
            else {
                s = sqrt(mgs[2]);
                if (s * s == a) {
                    return true;
                }
                else {
                    return false;
                }
            }
        }
        else {
            x = mgs[2] + mgs[1] * 10;
            s = sqrt(x);
            if (s * s == x) {
                return true;
            }
            else {
                return false;
            }
        }
    }
}
bool check(int m) {
    for (int i = 1; i<=9; i++) {
        ys[i] = m % 10;
        if (ys[i] == 3) {
            if ((m / 10) % 10 == 1) {
                return true;
            }
        }
        m = m / 10;
    }
    return false;
}


int main() {
    char a[10] = { 0 };
    char b[10] = { 0 };
    int m, n;
    cin >> m >> n;

    int front = 0;
    int back = 0;
    int flag = 0;
    for (int i = m; i <= n; i++) {
        front = i / 1000000;

        if (!checkprime(front)) {
            continue;
        }
        back = i % 1000;

        if (!checksqrt(back*1.0)) {
            continue;
        }
        if (check(i)) {
            continue;
        }
        flag++;
    }
    cout << flag << endl;
    return 0;
}