#include <iostream>
using namespace std;
int main() {
int y = 0, numbers, divizori, i, x;
cin >> x;
numbers = 2;
while(y < x) {
divizori = 0;
for(i = 1; i <= numbers; i++)
if(numbers % i == 0) {
divizori++;
}
if(divizori == 2) {
y++;
}
numbers++;
}
cout << numbers - 1;
return 0;
}
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