#!/usr/bin/env python
class primaryNumbers:
def nSet(self):
self.numSet = int(input())
def numIn(self, nSet):
self.dataA = []
self.dataB = []
for i in range(1, (nSet+1)):
lineInput = input()
temp = lineInput.split(' ')
self.dataA.append(int(temp[0]))
self.dataB.append(int(temp[1]))
def primaryCheck(self, aNum, bNum):
i = 0
self.table = []
self.count = 0
for testNum in range(aNum, (bNum+1)):
self.table.append(True)
for testNum in range(aNum, (bNum+1)):
if self.table[i]:
for x in range(2, (testNum)):
if testNum % x is 0:
multiple = int(bNum/testNum) - int(aNum/testNum)
if multiple is not 0:
for j in range(0, multiple):
self.table[i+(testNum*j)] = False
break
i += 1
for d in range(0, len(self.table)):
if self.table[d]:
self.count += 1
x = primaryNumbers()
x.nSet()
x.numIn(x.numSet)
for i in range(0, x.numSet):
x.primaryCheck(x.dataA[i], x.dataB[i])
print(x.count)
{"html5":"htmlmixed","css":"css","javascript":"javascript","php":"php","python":"python","ruby":"ruby","lua":"text\/x-lua","bash":"text\/x-sh","go":"go","c":"text\/x-csrc","cpp":"text\/x-c++src","diff":"diff","latex":"stex","sql":"sql","xml":"xml","apl":"apl","asterisk":"asterisk","c_loadrunner":"text\/x-csrc","c_mac":"text\/x-csrc","coffeescript":"text\/x-coffeescript","csharp":"text\/x-csharp","d":"d","ecmascript":"javascript","erlang":"erlang","groovy":"text\/x-groovy","haskell":"text\/x-haskell","haxe":"text\/x-haxe","html4strict":"htmlmixed","java":"text\/x-java","java5":"text\/x-java","jquery":"javascript","mirc":"mirc","mysql":"sql","ocaml":"text\/x-ocaml","pascal":"text\/x-pascal","perl":"perl","perl6":"perl","plsql":"sql","properties":"text\/x-properties","q":"text\/x-q","scala":"scala","scheme":"text\/x-scheme","tcl":"text\/x-tcl","vb":"text\/x-vb","verilog":"text\/x-verilog","yaml":"text\/x-yaml","z80":"text\/x-z80"}