#include<bits/stdc++.h>
#define Gc() getchar() 
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;using LL=__int128;
const int N=2e3+5,M=N*40+5,K=(1<<25)+5,mod=998244353,Mod=mod-1;const db eps=1e-9;const ll INF=1e18+7;mt19937 rnd(time(0));
ll x;int k,B[19];
ll dp[19][19][2][2],Po[19];
void Solve(){
	int i,j,h;scanf("%lld%d",&x,&k);
	Me(dp,0x3f);
	for(i=1;i<=18;i++) B[i]=x%10,x/=10;
	for(Po[0]=i=1;i<=18;i++) Po[i]=Po[i-1]*10;
	dp[0][0][0][0]=0;
	for(i=1;i<=18;i++){
		for(j=0;j<=k;j++){
			for(int o=0;o<2;o++)for(int p=0;p<2;p++){
				int w=B[i]+o;
				if(w<=9){
					dp[i][j][0][p]=min(dp[i][j][0][p],dp[i-1][j][o][p]);
					if(!p&&w<9) dp[i][j][0][1]=min(dp[i][j][0][1],dp[i-1][j][o][p]+Po[i-1]);
				} 
				if(j<k&&w){
					dp[i][j+1][1][1]=min(dp[i][j+1][1][1],dp[i-1][j][o][p]+Po[i-1]*(10-w));
				} 
			}
		}
	}
	ll ans=min(dp[18][k][0][1],dp[18][k][1][1]);
	if(ans>1e18) puts("-1");
	else printf("%lld\n",ans);
}
int main(){
	int t;
	scanf("%d",&t);
	// t=1;
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}