#include <iostream>
 
using namespace std;
 
int sito(int n)
{
    int i,j, tab[n];
    for(i=0; i<n; i++)
    {
        tab[i]=1;            // wstepne przygotowanie tablicy
    }
 
    for(j=2; j<n; j++)
    {
        int k=j;
        while(k<n)
        {
            k=k+j;                // wielokrotnosc danej liczby
            tab[k]=0;          // wyzerowanie wielokrotnosci
        }
    }
 
    int max = 0;
 
    for(i=2; i<n; i++)
        if (tab[i] == 1)
            max =  i;
    return max;
}
 
int main()
{
    cout << sito(10) << "\n";
    return 0;
}

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