#include<bits/stdc++.h>
#define int unsigned __int128
using namespace std;
inline int read(){
    char ch=getchar();int sum=0,f=1;
    while(!isdigit(ch))f=(ch=='-')?-1:1,ch=getchar();
    while(isdigit(ch))sum=(sum<<1)+(sum<<3)+(ch^48),ch=getchar();
    return sum*f;
}
void write(int x){
	if(x<0)putchar('-'),x=-x;
	if(x>9)write(x/10);
	putchar(x%10+48);
}
int T,a[42],dp[42][22][2];
int fast_pow(int x,int y){
	int res=1;
	for(;y;y>>=1,x=x*x)if(y&1)res=res*x;
	return res;
}
signed main(){
	T=read();
	while(T--){
		for(int i=0;i<=40;++i)a[i]=(int)0;
		memset(dp,0x3f,sizeof(dp));
		int op=dp[0][0][0];
		char jk[20];int k;scanf("%s",jk+1);int n=strlen(jk+1);k=read();
		for(int i=1;i<=n;++i)a[n-i+1]=jk[i]-'0';
		if(k==0){
			int czc=0;
			for(int i=n;i>=1;i--){
				if(a[i]==9) czc++;
				else break;
			}
			cout<<1;
			for(int i=1;i<=czc;i++){
				cout<<0;
			}
			cout<<endl;
			continue;
		}
		for(int i=0;i<=40;++i)dp[i][0][0]=0;
		for(int i=1;i<=39;++i)
			for(int j=0;j<=min(k,i);++j){
				if(j>=1)dp[i][j][1]=min((a[i]==0?dp[i-1][j-1][1]+(9-a[i])*fast_pow(10,i-1):dp[i-1][j-1][0]+(10-a[i])*fast_pow(10,i-1)),dp[i-1][j-1][1]+(9-a[i])*fast_pow(10,i-1));
				dp[i][j][0]=min(dp[i-1][j][0],(a[i]==9?dp[i-1][j][0]:dp[i-1][j][1]));
			}
		int ans=max((int)1,min(dp[39][k][0],dp[39][k][1]));
		if(ans==op)puts("-1");
		else write(ans),putchar('\n');
	}
	return 0;
}