#include <iostream>
#include <string>
#include <math.h>
using namespace std;
int liczbaTestow, dlugoscKodu;
string kod;
int znakZapytania;
bool znakZapytania_0;
int main()
{
cin >> liczbaTestow;
for (int j = 0; j < liczbaTestow; j++)
{
znakZapytania = 0;
znakZapytania_0 = 0;
cin >> dlugoscKodu >> kod;
if((kod[0]=='?') and (dlugoscKodu>1))
znakZapytania_0=true;
for(int i=0;i<dlugoscKodu;i++)
{
if(kod=="?")
znakZapytania++;
else if((kod[i]=='?') and (i!=0))
znakZapytania++;
}
if(znakZapytania_0==0)
cout << pow(10,znakZapytania);
else
cout << pow(10,znakZapytania)*9;
if (j!=liczbaTestow-1)
{
cout << endl;
}
}
return 0;
}
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