Problem:
Range Sum Query

Write a program which manipulates a sequence A = {a1, a2, . . . , an} with the following operations:

add(i, x): add x to ai.

getSum(s, t): print the sum of as, as+1,...,at.

Note that the initial values of ai (i = 1, 2, . . . , n) are 0.

Input

n q
com1 x1 y1
com2 x2 y2
...
comq xq yq

In the first line, n (the number of elements in A) and q (the number of queries) are given. Then, q queries are given where com represents the type of queries. '0' denotes add(xi, yi) and '1' denotes getSum(xi, yi).

Output

For each getSum operation, print the sum in a line.

Constraints

1 ≤ n ≤ 100000

1 ≤ q ≤ 100000

If comi is 0, then 1 ≤ xi ≤ n, 0 ≤ yi ≤ 1000.

If comi is 1, then 1 ≤ xi ≤ n, 1 ≤ yi ≤ n.

Sample Input 1

3 5
0 1 1
0 2 2
0 3 3
1 1 2
1 2 2

Sample Output 1

3
2

Solution in Ruby (judge verdict: Accepted)

N, Q = gets.split.map &:to_i
SqN = (N**0.5).to_i
K = N.fdiv(SqN).ceil
a = [0] * SqN * K
sq = [0] * SqN

$<.each{|s|
  com, x, y = s.split.map &:to_i
  x -= 1
  if com == 0
    # add
    a[x] += y
    sq[x / K] += y
  else
    # getSum
    sum = 0
    K.step(SqN * K, K){|r|
      l = r - K
      next if y <= l || r <= x
      if x <= l && r <= y
        sum += sq[r / K - 1]
      else
        # p [a,[x, l].max...[y, r].min]
        sum += a[[x, l].max...[y, r].min].sum
      end
    }
    p sum
  end
  # p [a,sq]
}