#include<iostream>
#include<sstream>
using namespace std;
int main()
{
string s;
cin >> s;
stringstream ss;
ss << s;
float num = 0;
ss >> num;
if(ss.good()) {
cerr << "No Valid Number" << endl;
}
else if(num == 0 && s[0] != 0) {
cerr << "No Valid Number" << endl;
}
else {
cout << num << endl;
}
}
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