include<bits/stdc++.h>

using namespace std; int n,m; int f[1001]; int ten(int len) {

int sum=1;
for(int i=1; i<=len; i++)
	sum*=10;
return sum;

} int main() {

scanf("%d%d",&n,&m);
for(int i=1; i<=n; i++) {
	scanf("%d",&f[i]);
}
for(int i=1; i<=m; i++) {
	int len,s,minn=INT_MAX;
	scanf("%d%d",&len,&s);
	for(int i=1; i<=n; i++)
		if(f[i]%(ten(len))==s)
			minn=min(minn,f[i]);
	if(minn==INT_MAX)
	minn=-1;
	printf("%d\n",minn);
}

return 0;

}