#include<stdio.h>
int get_grade(int a,int b){
	if(b < 16){
		a = a - 10;
		if(a < 10){
			a = 0;
		}
	}
	if(b > 20){
		int wrong = b - 20;
		a = a - wrong;
		if(a <= 0){
			a = 0;
		}
	}
	return a;
}
int main(){
	int n;
	scanf("%d",&n);
	int arr[100];
	for(int i = 0;i < n;i++){
		int a,b;
		scanf("%d%d",&a,&b);
		arr[i] = get_grade(a,b);
	}
	for(int i = 0;i < n;i++){
		printf("%d\n",arr[i]);
	}
	return 0;
}