#include <iostream>
#include <limits>
using namespace std;
int main() { int nr = 0;
while (!(std::cin >> nr)) {
std::cin.clear();
std::cin.ignore(std::numeric_limits<int>::max(), '\n');
std::cout << "Input is not number , try one more time: ";
}
std::cout << "Vector length: " << nr << std::endl;
return 0;
}
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