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: Wrong Answer)

def add(a, b, k, l, r, node)
  return 0 if r <= a || b <= l
  return node[k] if a <= l && r <= b
  m = (l+r)/2
  vl = add(a, b, 2*k+1, l, m, node)
  vr = add(a, b, 2*k+2, m, r, node)
  return vl + vr
end

n, q = gets.split.map(&:to_i)

m = 1
while m < n
  m *= 2
end
node = Array.new(2*m-1){0}

q.times{
  com, x, y = gets.split.map(&:to_i)
  x -= 1
  case com
  when 0
    k = x + m - 1
    node[k] += y
    while k > 0
      k = (k-1)/2
      node[k] += y
    end
  when 1
    puts add(x, y+1, 0, 0, m, node)
  end
}