#include<stdio.h>
int main()
{
int s;
scanf("%d",&s);
while(s--)
{
int j,i,sum,k,a[30];
long long n,m,t1,t2;
scanf("%lld%lld",&n,&m);
t1=t2=0;
while(n!=0)
{
t1+=n%10;
n/=10;
}
while(m!=0)
{
t2+=m%10;
m/=10;
}
sum=t1*t2;
while(sum>9)
{
k=sum;
sum=0;
while(k!=0)
{
sum+=k%10;
k/=10;
}
}
printf("%d\n",sum);
}
return 0;
}
int main()
{
int s;
scanf("%d",&s);
while(s--)
{
int j,i,sum,k,a[30];
long long n,m,t1,t2;
scanf("%lld%lld",&n,&m);
t1=t2=0;
while(n!=0)
{
t1+=n%10;
n/=10;
}
while(m!=0)
{
t2+=m%10;
m/=10;
}
sum=t1*t2;
while(sum>9)
{
k=sum;
sum=0;
while(k!=0)
{
sum+=k%10;
k/=10;
}
}
printf("%d\n",sum);
}
return 0;
}