var
ycl:array[1..8] of longint=(10,100,1000,10000,100000,1000000,10000000,100000000);
a:array[0..1000] of longint;
b:array[0..1000,1..2] of longint;
n,q,i,j:longint;
procedureqsort(l,r:longint);var
i,j,mid,t:longint;
begin
i:=l;
j:=r;
mid:=a[(l+r) div2];
repeatwhile a[i]<mid do inc(i);
while a[j]>mid do dec(j);
if i<=j thenbegin
t:=a[i];
a[i]:=a[j];
a[j]:=t;
inc(i);
dec(j);
end;
until i>j;
if i<r then qsort(i,r);
if l<j then qsort(l,j);
end;
begin
assign(input,'librarian.in');reset(input);
assign(output,'librarian.out');rewrite(output);
readln(n,q);
for i:=1to n doread(a[i]);
for i:=1to q doread(b[i,1],b[i,2]);
qsort(1,n);
for i:=1to q dobegin
j:=1;
while (a[j] mod ycl[b[i,1]]<>b[i,2]) and (j<=n) do inc(j);
if j>n then writeln(-1)
else writeln(a[j]);
end;
close(input);
close(output);
end.