z = input()
tablica_wynikow = []
for i in range(0,int(z)):
k = 0.0
reszta = 0
#x = "13 -5".split()
x = input().split()
x = [int(j) for j in x]
for r in range(0,abs(x[1])):
k = (x[0] - r)/x[1]
if k.is_integer() == True:
reszta = r
r = abs(x[1]) # konczy petle for
tablica_wynikow.append(reszta)
for y in tablica_wynikow:
print(y)
eiA9IGlucHV0KCkKdGFibGljYV93eW5pa293ID0gW10KZm9yIGkgaW4gcmFuZ2UoMCxpbnQoeikpOgoJayA9IDAuMAoJcmVzenRhID0gMAoJI3ggPSAiMTMgLTUiLnNwbGl0KCkKCXggPSBpbnB1dCgpLnNwbGl0KCkKCXggPSBbaW50KGopIGZvciBqIGluIHhdCglmb3IgciBpbiByYW5nZSgwLGFicyh4WzFdKSk6IAoJCWsgPSAoeFswXSAtIHIpL3hbMV0KCQlpZiBrLmlzX2ludGVnZXIoKSA9PSBUcnVlOgoJCQlyZXN6dGEgPSByCgkJCXIgPSBhYnMoeFsxXSkgIyBrb25jenkgcGV0bGUgZm9yCgkKCXRhYmxpY2Ffd3luaWtvdy5hcHBlbmQocmVzenRhKQoKZm9yIHkgaW4gdGFibGljYV93eW5pa293OgoJcHJpbnQoeSk=