Problem:
Score : 600 points

Problem Statement

Snuke is standing on a two-dimensional plane. In one operation, he can move by 1 in the positive x-direction, or move by 1 in the positive y-direction.

Let us define a function f(r, c) as follows:

f(r,c) := (The number of paths from the point (0, 0) to the point (r, c) that Snuke can trace by repeating the operation above)

Given are integers r_1, r_2, c_1, and c_2.
Find the sum of f(i, j) over all pair of integers (i, j) such that r_1 ≤ i ≤ r_2 and c_1 ≤ j ≤ c_2, and compute this value modulo (10^9+7).

Constraints

1 ≤ r_1 ≤ r_2 ≤ 10^6

1 ≤ c_1 ≤ c_2 ≤ 10^6

All values in input are integers.

Input

Input is given from Standard Input in the following format:

r_1 c_1 r_2 c_2

Output

Print the sum of f(i, j) modulo (10^9+7).

Sample Input 1

1 1 2 2

Sample Output 1

14

For example, there are two paths from the point (0, 0) to the point (1, 1): (0,0) → (0,1) → (1,1) and (0,0) → (1,0) → (1,1), so f(1,1)=2.

Similarly, f(1,2)=3, f(2,1)=3, and f(2,2)=6. Thus, the sum is 14.

Sample Input 2

314 159 2653 589

Sample Output 2

602215194

Solution in Python (3.4.3) (judge verdict: Runtime Error)

import sys
input = sys.stdin.buffer.readline
 
def main():
    a,b,c,d = map(int,input().split())
    MOD = 10**9+7
    N = c+d+5
    fac = [0 for i in range(N+1)]
    fac[0],fac[1] = 1,1
 
    for i in range(2,N+1):
        fac[i] = (fac[i-1]*i)%MOD
        
    def comb(x,f):
        return (fac[x+f]*pow(fac[x],MOD-2,MOD)*pow(fac[f],MOD-2,MOD))%MOD
 
    print((comb(c+1,d+1)-comb(c+1,b)-comb(d+1,a)+comb(a,b))%MOD)
    
if _name_ == "_main_":
    main()