#include <bits/stdc++.h>
#define getchar() (p1==p2&&(p2=(p1=buffer)+fread(buffer,1,1<<21,stdin),p1==p2)?EOF:*p1++)
using namespace std;
char buffer[1<<21],*p1,*p2;
inline int read(){int x=0,f=1;char ch=getchar();while(ch<48||ch>57){if(ch==45)f=-1;ch=getchar();}while(ch>=48&&ch<=57){x=x*10+(ch^48);ch=getchar();}return x*f;}
inline void write(int x){if(x<0){putchar(45);write(-x);return;}if(x>9)write(x/10);putchar(x%10^48);}
inline void writeln(int x){write(x),puts("");}
inline gcd(int a,int b){return gcd(b,a%b);}
inline exgcd(int a,int b,int&x,int&y){if(!b){x=1,y=0;return a;}int tmp=exgcd(b,a%b,y,x);y-=a/b*x;return tmp;}
inline qp(int a,int b,int p=1e9+7){int ret=1;for(;b;b>>=1,(a*=a)%=p)if(b&1)(ret*=a)%=p;return ret;}
inline int lowbit(int x){return x&-x;}
inline void solve();
#define MULT
#define int long long
signed main(){int T=1;
#ifdef MULT
T=read();
#endif
while(T--)solve();}
/*----free--*/
int l,r;
/*--unfree--*/
inline void solve(){
	l=read(),r=read();
	writeln((l+r)%9*(r-l+1)%9*5%9);
}

题目