#include <stdio.h>

long gcd(long x, long y);
long log_base2(unsigned long long num);

#define MAX 2000000

#define NUMPRIMES    148950
#define    SIEVE        250050
long primes[NUMPRIMES];    /* list of primes */
char bitArray[SIEVE];            /* bit array for checking off primes */
long primePos = 1;        /* statically 0 = 2 and 1 = 3 */
void sieve(unsigned long maxPrime)
{
    long i, temp;
    primes[0] = 2, primes[1] = 3; bitArray[0] = 169;
    temp = maxPrime>>3;
    for(i = 1 ; i <= temp ; i += 3) {
        bitArray[i]     = 171; bitArray[i+1]     = 186; bitArray[i+2]     = 174;
    }
    while(primes[primePos] < maxPrime) {
        for(i = primes[primePos]+1 ; i <= maxPrime ; i++)
            if( !( bitArray[ (i-1) >> 3 ] & (1<<( (i-1) & 7 )) ) )
                break;    /* Next prime has been reached */
        primes[++primePos] = temp = i;
        for(i = temp ; i <= maxPrime ; i += temp+temp)
            bitArray[ (i-1) >> 3 ] |= ( 1 << ( (i-1) & 7 ) );
    }
}
long log_base2(unsigned long long num)
{
    unsigned long long prod = 1;
    long i;
    for(i = 0 ;  ; i++) {
        if(prod >= num)
            break;
        prod <<= 1;
    }
    return i;
}
int main()
{
    long n;
    long i, j, temp;
    unsigned long long count = 0;
    long totients[MAX];

    sieve(2000000);
    scanf("%ld", &n);

    for(i = 0 ; i <= n ; i++) totients[i] = i;

    for(i = 0 ; primes[i] <= n ; i++) totients[primes[i]] = primes[i]-1;

    for(i = 0 ; (temp=primes[i]+primes[i]) <= n ; i++) {
        for(j = temp ; j <= n ; j+=primes[i]) {
            totients[j] /= primes[i];
            totients[j] *= (primes[i]-1);
        }
    }

    for(i = 2 ; i <= n ; i++) {
        count += (unsigned long long)totients[i];
    }

    printf("%ld", log_base2(count));
    return 0;
}