#include <iostream>
using namespace std;
int main()
{
long long n;
cin >> n;
bool z = false;
long long zc = 0;
string nb;
for(long long i = 0; i < n; i++)
{
bool f = false;
string x;
cin >> x;
if(x[0] == '1')
{
f = true;
}
else if(x[0] == '0')
{
z = true;
break;
}
else
{
nb = x;
}
if(f)
{
for(long long j = 1; j < x.size(); j++)
{
if(x[j] == '0')
{
zc++;
}
else
{
nb = x;
break;
}
}
}
}
if(z)
{
cout << "0" << endl;
}
else
{
if(nb.size() != 0)
{
cout << nb;
}
else
{
cout << "1";
}
for(long long i = 0; i < zc; i++)
{
cout << "0";
}
cout << endl;
}
return 0;
}
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