#include <stdio.h>

unsigned N, M;

int main() {
    double rate;
    int c;
    unsigned low, high, idx;
    int ratio, temp;

    scanf("%d", &c);
    for(; c>0; c--) {
        scanf("%d %d", &N, &M);
        rate = (double)M/N*100;
        ratio = (unsigned)rate;

        //printf("%f, %d\n", rate, ratio);

        low=1;
        high=2000000000;

        while(1) {
            idx=(low+high)/2;       
            rate = (double)(M+idx)/(N+idx)*100;
            temp = (unsigned)rate;

            if(low >= high) break;

            if( temp >= ratio+1) {
                high = idx;             
            }
            else {
                low = idx+1;                
            }

        }

        if(temp == ratio+1) printf("%u\n", idx);
        else printf("-1\n");

        //printf("%f, %d, %d\n", rate, ratio+1, temp);
    }
    return 0;
}