f1.cpp

#include <cstdio>
using namespace std;
 
int N;
int citatel;
int jmenovatel;
 
int NSD(int a, int b)
{
    if(a < b)
    {
        int tmp = a;
        a = b;
        b = tmp;
    }
    int c = a%b;
    //printf("   -== %d %d %d\n", a, b, c);
    while(c != 0)
    {
        //printf("   --- %d %d %d\n", a, b, c);
        a = b;
        b = c;
        c = a%b;
    }
    return b;
}
 
int main()
{
    getchar();
    getchar();
    scanf("%d", &N);
 
    int cit_new, jmen_new;
    int nsd, nsd2;
 
    int pocet = 0;
 
    /**
    for(int i=1; i<=10000; i++)
    {
        for(int j=i; j<=10000; j++)
        {
            if(i*j > N*(i+j))
            {
                //printf("Break: 1/%d + 1/%d\n", i, j);
                ; //break;
            }
 
            // mensi
            cit_new = i+j;
            jmen_new = i*j;
 
            nsd = NSD(jmen_new, cit_new);
            cit_new /= nsd;
            jmen_new /= nsd;
 
            if(cit_new == 1 && jmen_new == N)
            {
                pocet++;
                printf("Nalezeno! 1/%d + 1/%d\n", i, j);
            }
        }
    }
    **/
 
 
 
    //int a=2*N, b=2*N;
    pocet = 1;
 
    int b_cit, b_jmen;
 
    for(int a=2*N-1; a>N; a--) // pocminka ??
    {
        b_cit = a*N;
        b_jmen = a-N;
 
        nsd = NSD(b_cit, b_jmen);
        //printf("... cit=%d, jmen=%d, nsd=%d\n", b_cit, b_jmen, nsd);
        if(nsd == b_jmen)
        {
            pocet++;
            //printf("Nalezeno! 1/%d + 1/%d\n", a, b_cit/b_jmen);
        }
    }
 
    printf("%d\n", pocet);
 
    return 0;
}