//Beiland Arnold
#include <fstream>
using namespace std;
inline const short usz(const short x);
int main(){
ifstream fin("cifra.in");
ofstream fout("cifra.out");
short T;
fin>>T;
char c;
fin.get(c); // '\n'
while(T--){
char penult='0', ult='0';
fin.get(c);
while(c!='\n'){
penult=ult;
ult=c;
fin.get(c);
}
fout<<usz(10*penult+ult-528)<<'\n';
}
fout.close();
fin.close();
return 0;
}
/* aceasta e ideea
short usz(const short x){
short retval=0;
static const short par[]={0, 1, 4, 7, 6, 5, 6, 3, 6, 9}; //penultima cifra
static const short impar[]={0, 1, 6, 3, 6, 5, 6, 7, 4, 9};
for(short i=1;i<=x;i++){
if(i>10&&i/10%2) retval+=impar[i%10];
else retval+=par[i%10];
retval%=10;
}
return retval;
}
*/
// cu calcule deja facute:
inline const short usz(const short x){
static const short retval[]={0, 1, 5, 2, 8, 3, 9, 2, 8, 7,
7, 8, 4, 7, 3, 8, 4, 1, 5, 4,
4, 5, 9, 6, 2, 7, 3, 6, 2, 1,
1, 2, 8, 1, 7, 2, 8, 5, 9, 8,
8, 9, 3, 0, 6, 1, 7, 0, 6, 5,
5, 6, 2, 5, 1, 6, 2, 9, 3, 2,
2, 3, 7, 4, 0, 5, 1, 4, 0, 9,
9, 0, 6, 9, 5, 0, 6, 3, 7, 6,
6, 7, 1, 8, 4, 9, 5, 8, 4, 3,
3, 4, 0, 3, 9, 4, 0, 7, 1, 0};
return retval[x];
}