#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int gcd(int a, int b) {
    if (b == 0) {
        return a;
    } else {
        return gcd(b, a % b);
    }
}

int v1(int n) {
    int fractionsCount = 0;
    for (int a = 1; a <= n; ++a) {
        int count = 0;
        for (int b = 1; b <= n; ++b) {
            if (gcd(a, b) == 1) {
                fractionsCount++;
                count++;
            }
        }
    }
    return fractionsCount;
}

int v2(int n) {
    if (n == 1) {
        return 1;
    }
    int fractionsCount = n;
    int primeDivisors[8];
    int primeDivisorsCount = 0;
    int *array = calloc(n, sizeof(int));
    for (int num = 2; num <= n; ++num) {
        primeDivisorsCount = 0;
        int clone = num;
        if (clone % 2 == 0) {
            primeDivisors[primeDivisorsCount++] = 2;
            do {
                clone >>= 1;
            } while (clone % 2 == 0);
        }
        for (int div = 3; div <= clone; div += 2) {
            if (clone % div == 0) {
                primeDivisors[primeDivisorsCount++] = div;
                do {
                    clone /= div;
                } while (clone % div == 0);
            }
        }
        switch (primeDivisorsCount) {
            case 0:
                fractionsCount += n - n / num;
                break;
            case 1:
                fractionsCount += n - n / primeDivisors[0];
                break;
            case 2:
                fractionsCount +=
                        n - (n / primeDivisors[0] + n / primeDivisors[1] - n / (primeDivisors[0] * primeDivisors[1]));
                break;
            default: {
                memset(array, 0, n * sizeof(int));
                for (int index = 0; index < primeDivisorsCount; ++index) {
                    for (int i = primeDivisors[index]; i <= n; i += primeDivisors[index]) {
                        array[i - 1] = 1;
                    }
                }
                for (int index = 0; index < n; ++index) {

                    if (array[index] == 0) {
                        fractionsCount++;
                    }
                }
            }
                break;
        }
    }
    free(array);
    return fractionsCount;
}

int main() {
    char *inFileName = "fractii.in";
    char *outFileName = "fractii.out";
    FILE *in = fopen(inFileName, "r");
    if (in == NULL) {
        printf("Cannot open %s.\n", inFileName);
        return 1;
    }
    FILE *out = fopen(outFileName, "w");
    int n;
    fscanf(in, "%d", &n);
    if (n == 1) {
        fprintf(out, "1");
    } else {
        fprintf(out, "%d", v2(n));
    }
    fclose(in);
    fclose(out);
    return 0;
}