import bisect
from collections import defaultdict

def main():
    import sys
    input = sys.stdin.read
    data = input().split()
    idx = 0
    n = int(data[idx])
    idx += 1
    
    blue_dict = defaultdict(list)
    red_s_list = []
    
    for _ in range(n):
        a = int(data[idx])
        b = int(data[idx+1])
        t = int(data[idx+2])
        idx += 3
        if a == 0:
            s_i = b - t
            red_s_list.append(s_i)
        else:
            s_j = b - t
            blue_dict[s_j].append(t)
    
    for key in blue_dict:
        blue_dict[key].sort()
    
    result = 0
    
    for s_i in red_s_list:
        if s_i in blue_dict:
            target_list = blue_dict[s_i]
            k = -s_i
            count = len(target_list) - bisect.bisect_left(target_list, k)
            result += count
    
    print(result)

if __name__ == '__main__':
    main()